03 05 APRIL BLED, SLOVENIA THE PROCEEDINGS OF THE AUSTRIAN -SLOVENIAN POLYMER MEETING 2013 WWW.ASPM.SI ASPM 2013 AUSTRIAN - SLOVENIAN POLYMER MEETING ORGANISERS 9 Center of Excellence PoliMaT® Polymer Materials and Technologies 0 REPUBLIC OF SLOVENIA MINISTRY OF EDUCATION, SCIENCE, CULTURE AND SPORT ing in your future OTHWIION EAKT FINANCED BYTHE EUBCKAN UNION European Regional DeuEtopment Fund PCCL Polymer Competence Center Leoben <2) Slovensko kemijsko društvo Slovenian Chemical Society Kemijski inštitut National Ljubljana Institute of Chemistry Slovenija Slovenia SPONSORS Waters THE SCIENCE OF WHAT'S POSSIBLE.7* 15 j ON A GOOD ROAD I A YEARS GOODYEAR DUNLOP Instruments NETZSCH Anton Paar EGONYL d.o.o. 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SLOVENIA. 3-5 APRIL. 2013 The Proceedings of the Austrian - Slovenian Polymer Meeting 2013 Austrian - Slovenian Polymer Meeting - ASPM 2013 3-5 April 2013 Bled, Slovenia www.aspm.si info@aspm.si Editors: Majda Žigon Teja Rajšp Cover design: Alenka Paveo Publisher: Centre of Excellence PoliMaT Tehnološki park 24 1000 Ljubljana Slovenia www.polimat.si © Centre of Excellence PoliMaT, 2013 CIP - Kataložni zapis o publikaciji Narodna in univerzitetna knjižnica, Ljubljana 678.7(082)(0.034.2) AUSTRIAN - Slovenian Polymer Meeting (2013 ; Bled) The proceedings of the Austrian - Slovenian Polymer Meeting 2013 [Elektronski vir] / Austrian - Slovenian Polymer Meeting - ASPM 2013, 3-5 April 2013, Bled, Slovenia ; editors Majda Žigon, Teja Rajšp. - El. zbornik. - Ljubljana : Centre of Excellence PoliMaT, 2013 ISBN 978-961-269-992-5 (pdf) 1. Gl. stv. nasi. 2. Žigon, Majda 266351872 ** AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 TABLE OF CONTENTS PLENARY LECTURES............................................................................................................ 1 KEYNOTE LECTURES............................................................................................................4 LECTURES..........................................................................................................................19 POSTERS.........................................................................................................................135 PRESENTING AUTHORS INDEX..........................................................................................302 BLED, SLOVENIA, 3-5 APRIL, 2013 PLENARY LECTURES PL 1 Sustainable biobased materials Ann-Christine Albertsson*, Ulrica Edlund Fibre and Polymer Technology, Royal Institute of Technology (KTH), Stockholm, Sweden *aila@kth.se Global and major challenges for future material resource sustainability are to secure building block resources other that fossil and to minimize the accumulation of plastic waste. One approach is to develop materials by mimicking commodity plastics while replacing the oil refinery with a bio refinery. It is possible to use monomers, pre-polymers and polymers from nature but limiting factor so far has often been the recovery and purification of biomass derived molecules without using too much solvents and energy. It has also to be done without conflict with food supply. Instead of building up a new industry based on a bio refinery and virgin biomass we have focused on existing industry and the use of crude biomass released to process water and side streams. We have shown how it is possible to upgrade waste waters in a cheap way and recover hemicellulose rich fractions useful for making microspheres, hydrogels, and barrier films. Making inexpensive, yet functional and competitive materials from biomass require innovative approaches. References [1] Saadatmand, S., Edlund, U., Albertsson, A.-C., Polymer 2011, 52, 4648. [2] Edlund, U., Svensson, M., Albertsson, A.-C., Eur. Polym. J. 2012, 48(2), 372. [3] Edlund, U., Yu, Y., Ryberg, Y. Z., Krause-Rehberg, R., Albertsson, A.-C., Anal. Chem. 2012, 84(8), 3676. [4] Ibn Yaich, A., Edlund, U., Albertsson, A.-C. Biomacromolecules 2012, 13, 466. [5] Edlund, U., Albertsson, A.-C., J. Polym. Sci. A Polym. Chem. 2012, 50, 2650. [6] Saadatmand, S., Edlund, U., Albertsson, A.-C., Danielsson, S.; Dahlman, O., Environ. Sci. Technol. 2012, 46(15), 8389. [7] Ryberg, Y. Z., Edlund, U., Albertsson, A.-C., Biomacromolecules 2012,13(8), 2570. [8] Edlund, U., Rodriguez-Emmenegger, C., Brynda, E., Albertsson, A.-C., Polym. Chem. 2012, 3(10), 2920. [9] Ibn Yaich, A., Edlund, U. Albertssson,A.-C., Carbohydr. Polym. 2013, in press. PL 2 Synthesis and self-assembly of well-defined copolypeptides Nikos Hadjichristidis King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia Block copolypeptides, which combine the self assembly of block copolymers and the highly ordered 3D structures of proteins, are potential candidates for novel supramolecular structures and biotech applications, such as biosensors, tissue engineering, and selective drug delivery. Attempts to synthesize well-defined polypeptides by the ring-opening polymerization of a-amino acid N-carboxyanhydrides (NAC) with primary amines, have been plagued by unwanted side reactions for more than fifty years. Recently, we have shown that the ring opening polymerization of a-amino acid N-carboxyanhydrides (NCAs) with n-hexylamine using high vacuum (HV) techniques, leads to high molecular weight, well-defined living polypeptides in ~100 % yield with low polydispersity. The method is a general one, leading to molecules with high structural complexity, which will facilitate the design of biologically active molecules. The synthesis of a few block copolypeptides and macromolecular chimeras, as well as their self-assembly in bulk and in water will be discussed. References Biomacromolecules, 5, 1653 (2004); 6, 2352 (2005); 7, 3379 (2006); 8, 2173 (2007); 9, 1959 (2008); 9, 2072 (2008) ; 12, 2396 (2011). Chem. Rev., 109, 5528 (2009). Angew.Chem., 50, 2516 (2011). Macromolecules, 43, 1874 (2010) ; 43, 9071 (2010) ; 45, 2850 (2012). AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 PL 3 Polyvinylphosphonic acid (PVPA) - the challenge to create a polyelectrolyte for advanced technologies Gerhard Wegner* Max-Planck-Institute for Polymer Research D-55128 Mainz/Germany *wegner@mpip-mainz.mpg.de 1. Introduction Poly(acrylic) (PA), Poly(vinylsulfonic acid) (PVS) and poly(vinylphosphonic acid) (PVPA) are a series of analogous polymers of prototype structure and are paradigmatic polyelectrolytes. While literature and applications concerning PA are legion, this is less true for PVS. Astoundingly, PVPA was barely known and only scarce information on its synthesis, properties and structure was available before 2006. Interest in its potential as component of low-temperature fuel cells prompted our attention. 2. Synthesis and Properties In 2006 Bahar Bingol [1] succeeded in our laboratory [2-4] to develop a synthesis for high molecular weight PVPA and simultaneously gave the mechanistic clue why previous workers had failed in their attempts of synthesis Bingol explored the direct free radical polymerization of VPA (2) to PVPA (1). Realizing that it is the VPA-anhydride which undergoes cyclopolymerization she was able for the first time to obtain high mol. wt. PVPA. Later it was shown by W. Meyer et al [6] that anionic polymerization of VPA-esters is possible and HMW-PVPA can be obtained via saponification of the poly(phosphonates). -(-HjC-CH-JB POjHj 1 OH OH 5 (a) n H2C=CH ■ O=P(OCHj)j 3 -fHjC-CH-jn O=P(OCHj)j 4 O" CH CH ssPv P O R—CH, CH-CH—CH,* OHO OH (c) 2 + HO n H,C=CH pO H 3 '2 POH 2 R-CH OHO OH R + 5 More recently B. Rieger et al. [7] have reported that Diethyl VPA can be polymerized using specific rare-earth metal catalysts via (probably) a GTP-mechanism and saponification of the product yields HMW-PVPA as well. A comprehensive review is available [8]. PVPA acts as a medium-strong monobasic acid, comparable to PA. However, it has considerable interest as a material for the design of fuel cells as it shows good proton conductivity and temperature stability [2], [5]. Further work demonstrated the formation of copolymers and hydrogels [5] pointing into the direction of biocompatible materials. The presentation summarizes the recent developments under the auspices of material science devoted to advances materials. References [1] Synthesis, microstructure, and acidity of poly(vinylphosphonic acid) Bingol B., Meyer W., Wagner M., Wegner G., Macromol. RC 2006, 27, 1719-24 [2] High-resolution solid-state NMR studies of poly(vinylphosphonic acid) proton-conducting polymer: Molecular structure and proton dynamics, Lee Y.J, Bingol B., Wegner G. et al., J. Phys. Chem. B 2007, 111, 9711-21 [3] Copolymers and hydrogels based on vinylphosphonic acid Bingol B., Strandberg C., Szabo A., Wegner G., Macromolecules 2008, 41, 2785-2790 [4] Characterization of oligo(vinyl phosphonate)s by high-resolution electrospray ionization mass spectrometry Bingol B. et al, Macromolecules 2008, 41, 1634-39 [5] Water sorption of poly(vinylphosphonic acid) and its influence on proton conductivity Kaltbeizel A., Bingol B., Wegner G. et al, Solid State Ionics 2007, A 178, 469-474 [6] VPA Homo- and Block Copolymers, Wagner Th., Meyer W., et al., Macromol. Chem. Phys. 2009, 210, 1893-1914 [7] Rieger B. et al., Angew. Chem. Int. Ed. 2010, 49, 1489-1491 [8] Macarie L., Ilia G., Progr. Polym. Sci. 2010, 35, 1078-1092 BLED, SLOVENIA, 3-5 APRIL, 2013 PL4 Directed assembly of block copolymer thin films for nanotechnology applications Gurpreet Singh (1 ), Kevin G. Yager (2 ), Detlef-M. Smilgies (3 ), Manish M. Kulkarni (1 ), David G. Bucknall (4) and Alamgir Karim (1 ) (1) Department of Polymer Engineering, University of Akron (UA), Akron, OH 44325, USA (2) Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA (3) Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, New York 14853, USA (4) Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA Fabricating ordered nanodomains of multi-component polymer thin films on diverse substrates via continuous processing methods is particularly attractive for nanomanufacturing of next-generation electronics. We report such a method, termed cold-zone annealing (CZA) utilizing a dynamic sharp thermal gradient (~ 45 oC/mm) (i.e. CZA-S). This method applied to block copolymers (BCP) allows for production of etchable and vertically oriented cylindrical domains of poly(styrene-b-methylmethacrylate) in 1100-1000| nm thick films on low thermal conductivity rigid (quartz) and flexible (PDMS, Kapton) substrates. Competing substrate wetting interactions dominate BCP orientation in films below 100 nm while broadening of the thermal gradient profile in films thicker than 1000 nm leads to loss of vertical orientation. An optimal dynamic sweep rate (~ 5 icron/s) produces the best vertical order. At too fast a sweep rate (> 10 micron/s) the BCP film ordering is kinetically hindered, while at too slow a sweep rate (< 1 micron/s), polymer relaxation and preferential surface wetting dynamics favor parallel BCP orientation. Equivalently static gradient conditions produces vertically aligned BCP cylinders only at the maximum T. CZA-S mechanism involves propagating this vertically oriented BCP zone across the sample. We also report the discovery of a rapid and continuous dynamic thermal gradient process, termed as Cold Zone Annealing - SoftShear "CZA-SS", to directionally align cylindrical block copolymer (BCP) films on rigid and flexible substrates. In CZA-SS, BCP films are confined under a soft-shear polydimethylsiloxane (PDMS) layer and subsequently zone annealed to obtain defect-free unidirectional horizontal cylinders over large areas (> 50 cm2). AFM and GISAXS analysis reveal > 95% aligned orientational order with an angular spread of < 9 degrees FWHM. This orientational order is preserved even for thick films (> 1 m) on flexible substrates at extremely high processing speeds (~ 0.2 mm/s), essential for scale-up to roll-to-roll manufacturing purposes. Extensions of the method to other multicomponent polymer systems are in progress. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED. SLOVENIA. 3-5 APRIL. 2013 KEYNOTE LECTURES KNL1 Non-linear macromolecules of controlled structure and high functionality Andrzej Dworak*. Wojciech Walach, Agnieszka Kowalczuk, Barbara Trzebicka Polish Academy of Sciences, Centre of Polymer and Carbon Materials, 41-812 Zabrze, Poland * a ndrzej.dworak@cmpw-pan.edu.pl 1. Introduction Non-linear macromolecules have aroused considerable interest both from the fundamental point of view and from the point of view of their envisaged applications [la-c]. They were considered to constitute a polymer chemistry response to the dendrimers, perfectly symmetric and uniform macromolecules of promising properties, but tedious to synthesize. Non-linear macromolecules differ in their properties from chain-like ones. They are not able to adopt the coil-like conformation, as they do not consist of a single chain and assume a more compact conformation, thus influencing the properties of both bulk and in solution. They have on their outside numerous functional groups, capable of undergoing modification reactions and deciding about the interactions with the surrounding medium (solubility). They may assume a core-corona structure (unimolecular micelles), thus being prospective carriers for active species. Even if no decisive breakthrough has been achieved, they constitute an interesting and living subject of research both in the academia and in the industry. The subject of this contribution is to discuss the synthesis and properties of highly hydroxyl functional, hydrophilic and amphiphilic star-like and hyperbranched polyethers. 2. Building blocks Following polyethers have been incorporated into the star and HB macromolecules: The monomers selected were capable to undergo living anionic polymerizations (substituted oxiranes) or controlled radical, also self-condensing polymerizations (styrene and derivatives). The monomers were bearing functional groups, frequently protected for sake of the polymerization control, to introduce requested hydrophilicity to open modification possibilities necessary to imprint desired functions: —(CH2-CH2-O)— PEO units -(CH-CH2-0)-I ch2 OR R= H, t-Bu, -(CH-CH2)- PS units 3. Structures obtained Basing upon this blocks and applying living polymerization of corresponding oxiranes following structures were obtained and their properties in solution studied: Stars [2a-c] and dendritic stars [2d] of hydrophobic (red on schemes) core and hydrophilic (blue on schemes) shell with up to 1200 OH groups were obtained. Some of them are thermosensitive and the cloud point depends on the structure and hydrophilic/hydrophobic units ratio. Due to their polar character they self-organize in solutions, a process which may be at least partially controlled, and are able to transport hydrophobic species. Well defined dendritic block copolymer of poly(ethylene oxide) and highly functional polyglycidol corona were obtained [3]. This strongly hydrophilic copolymer with high content of functional hydroxyl group is soluble also in nonpolar organic solvents. Pom-pom-like poly(ethylene oxide) with oligoglycidol branching blocks achieve molar mass up to 200 000 and more than 400 OH groups per molecule [4]. BLED, SLOVENIA, 3-5 APRIL, 2013 1. a) A. Hult et al., Adv. Polym. Sci. 1999, 143, 1; b) S.-E. Stiriba et al., Angew. Chem. Int. Ed. 2002, 41, 1329; c) C. Gao, D. Yan, Prog. Polym. Sci. 2004, 29, 183. 2. a) A. Dworak et al., Polym. Bull. 2002, 49, 9; b) M. Jamroz-Piegza et al.,J. Colloid Interface Sci. 2008, 325, 141; c) M. Libera et al., Polymer 2011, 52, 250; d) M. Libera et al., Polymer 2011, 52, 3526. 3. A. Dworak, W. Walach, Polymer 2009, 50, 3440. 4. W. Walach, B. Trzebicka, J. Justynska, A. Dworak, Polymer 2004, 45, 1755. KNL 2 Functional materials from polysaccharides Volker Ribitsch (1) and Karin Stana-Kleinschek (2 ) (1) Institute of Chemistry, Karl-Franzens-University Graz, HeinrichstraGe 28/III, AT-8010 Graz, Austria (2) Laboratory for Characterization and Processing of Polymers, Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia Polysaccharides show versatile physicochemical properties and can be used for many applications ranging from packaging to functional coatings. This presentation gives an overview about the different ways to design new material using compounding processes. Cellulosic materials such as cellulose films or cellulose acetate membranes can be modified on their surface in order to introduce new properties. An aqueous layer by layer coating with positively charged polysaccharides and negatively charged nano-clay platelets for instance, can be used as a barrier coating for water vapour and cellulose acetate membranes can be modified with chitosan and carboxymethyl cellulose, to generate anti-fouling or anti-microbial coatings. Furthermore cellulose itself has several unique properties. Its special chemical and physical structure makes it an ideal candidate for the production of hydrophilic but insoluble nanometric surface coatings on solid substrates. One of the methods to produce such structures is to coat cellulose derivatives on substrates and subsequently regenerate these coatings to pure cellulose. Various thin films of cellulose can be produced and characterized with respect to their surface properties using contact angle measurements and X-ray photoelectron spectroscopy. These films can micro-structured using lithographic processes in combination with enzymatic digestion. Furthermore structure property relationships of cellulosic bulk materials can be elucidated by small or wide angle X-ray scattering (SWAXS) whereas surface characteristics and orientation effects can be studied by gracing incidence small or wide angle X-ray scattering (GI-SWAXS). As another example cellulose acetate nanoparticles with incorporated functional polysaccharides can be manufactured. These particles show an outstanding application potential for targeted drug delivery and antimicrobial or antifouling surface coatings. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 214653. KNL 3 Regioselective functionalization of polymer constructs with growth factor peptides for regenerative medicine: gels, fibers & scaffolds Matthew L. Becker Department of Polymer Science, The University of Akron, USA Center for Biomaterials in Medicine, Austen Bioinnovation Institute in Akron, USA Stem cells respond to many cues from their microenvironment, which may include chemical signals, mechanics, and topography. Importantly, these cues may be incorporated into scaffolding to control stem cell differentiation and optimize their ability to produce tissues in regenerative medicine applications. Despite the significant amount of work in this area, the materials have been primarily static and uniform. The number of rationally designed and translationally-relevant materials emerging from research laboratories remains limited. To this end, we have developed a number of technologies that include the ability to attach highly functional and bioactive groups to polymer constructs that include hydrogels, fibers and polymeric scaffolds. All are degradable and designed to be restorative or therapeutic in nature. This presentiaton will highlight our recent efforts in this area. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 KNL 4 Alkyd technology Mark D. Soucek* Department of Polymer Engineering, University of Akron, Akron, OH 44313, USA *msoucek@uakron.edu Research in biomass derived coatings account for ~1/3 of the Soucek group research portfolio. The Soucek group has reported on extensively on the functionalization of seed oils to prepare reactant diluents for coatings. Reactive diluents perform the role of an organic solvent without volatizing into the atmosphere, and unlike organic solvents participate in the crosslinking process during film formation. Using simple Diels-Alder Chemistry, autoxidative, UV-curable, and moisture curable reactive diluents have successfully prepared and integrated into coating systems. Colloidal additives which can react autoxidatively or via thiol-ene chemistry. In addition to reactive diluents, controlled polymerization (RAFT) has been utilized to create acrylic-alkyd hybrids suitable for both waterborne and solventborne media. In this talk, I will present a multiscale method, based on the flux-exchange coupling, which concurrently links atomistic, mesoscopic, and continuum models of liquids [1,2]. Our approach enables the insertion of large molecules into the atomistic domain via a mesoscopic region and it allows for molecular simulations either in the grand-canonical ensemble or under non-equilibrium conditions. The applicability of the method will be demonstrated on an open molecular dynamics simulation of a star polymer melt where we open up the molecular system to exchange mass and momentum with its surroundings. Figure 1. An equilibrated system of star polymer melt [3]. Acknowledgements Financial support through the Grants J1-4134 and P1-0002 from the Slovenian Research Agency is acknowledged. References [1] R. Delgado-Buscalioni, K. Kremer, M. Praprotnik, J. Chem. Phys. 2008, 128, 114110. [2] R. Delgado-Buscalioni, K. Kremer, M. Praprotnik, J. Chem. Phys. 2009, 131, 244107. [3] J. Sablic, B.S. Thesis, University of Ljubljana, 2012. KNL 5 Open molecular dynamics simulation of star polymers Matej Praprotnik* National Institute of Chemistry, Hajdrihova 19, SI-1001, Ljubljana, Slovenia *praprot@cmm.ki.si * BLED, SLOVENIA, 3-5 APRIL, 2013 KNL 6 Utility of chromatographic and spectroscopic techniques for a detailed characterization of poly(styrene-b-isoprene ) miktoarm star copolymers with complex architecture Ema Žagar (1,2 ) *, David Pahovnik (1) and Majda Žigon (1,2) (1) Laboratory for Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia (2) Centre of Excellence for Polymer Materials and Technologies, Tehnološki park 24, SI-1000 Ljubljana, Slovenia *ema.zagar@ki.si This lecture focuses on a detailed characterization of poly(styrene-b-isoprene) (PS(PI)x) miktoarm star copolymers which were synthesized by anionic polymerization of polystyrene (PS) and polyisoprene (PI) blocks and selective chlorosilane coupling chemistry. The PS(PI)x star copolymers consist of one long PS block and different number of shorter PI blocks (x = 2, 3, 5 and 1). PS(PI)x star copolymers differ also in the length of PI block, which decreases with the number of PI blocks in the star copolymer. Our aim was to determine the purity of samples and to identify exactly the constituents of individual samples. For this purpose we used a variety of separation techniques (size-exclusion chromatography (SEC), reversed-phase liquid-adsorption chromatography (RP-LAC) and two-dimensional liquid chromatography (2D-LC)), and characterization techniques (UV-MALS-RI multi-detection SEC system, NMR and MALDI-TOF MS). The results of our research work show that detailed characterization of complex polymers requires a comprehensive study, comprising not only the spectroscopic techniques but also efficient chromatographic techniques hypenated with multi-detection systems. KNL 7 Thiol-ene polymerization of biocompatible monomers in additive manufacturing technology Robert Liska* Vienna University of Technology, Institute of Apllied Synthetic Chemistry, Austria *Robert.liska@tuwien.ac.at 1. Introduction UV curing of photopolymerizable formulations has been used for more than a half century for protective and decorative coatings of paper, wood, metals or plastics. Advantages can for sure been found in the high curing speed that allows the conversion of typically (meth)acrylate-based monomers within the fraction of a second. Furthermore, a large variety of monomers is commercially available so that the mechanical properties and other polymer characteristics can be easily tuned. Thiol-Ene polymerization is also known since the 50's of the last century and has gained tremendously increasing interest during the last decade, thanks to the rediscovery by Hoyle [1] and recent efforts by Bowman [2]. Advantages such as low oxygen inhibition and shrinkage, uniform networks with significantly improved mechanical properties are accompanied by up to now unsolved disadvantages such as unpleasant odour and poor storage stability. 2. Results and discussion This presentation will give an overview on new aspects in thiol-ene polymerization. On the one hand we were able to introduce a new concept in thiol-ene stabilization which gives excellent storage stability with nearly no increase in viscosity with several months up to one year [3]. Very recently we have demonstrated that vinylesters and vinylcarbonates [4] are a promising class of new, low toxic monomers not only for biomedical applications [5] but also for classical coatings. The only limitation of moderate reactivity between those of methacrylates and acrylates has been circumvented by thiol-ene polymerization [6]. Degradation can be easily tuned giving nontoxic low molecular polyvinyl alcohol as degradation product and various non-toxic alcohols such as glycerol or polyethylene glycol. In vivo experiments demonstrated excellent biocompatibility. If one wants to have arbitrarily shaped 3D cellular structures, additive manufacturing technology (AMT), also called Rapid Prototyping, is the method of choice. Different setups are commercially available that allow the printing of photopolymerizable formulations from a simple CAD model. Laser or DLP (Digital light processing) based systems fabricate polymer parts with a feature resolution of about 10 |im. In recent days not only prototypes are of interest, also small number of individual parts that can be used in the automotive industry or for medical applications are important. For the 3D printing process, the rather new two photon polymerization technique has also gained increasing interest during the last year. Especially the recently demonstrated significant increase in writing speed [1] will make it nowadays interesting for translation into industrial processes. With newly designed two photon initiators we were also able to show the 3D printing of vinylester-modified gelatine with free thiol-groups of bovine serum albumin, for potential tissue engineering application. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 References 1. Hoyle, C. E.; Hensel, R. D.; Grubb, M. B. J Polym Sci, Polym Chem (1984), 22(8), 1865-73 2. Cramer, Neil B.; Bowman, Christopher N. J Polym Sci, Polym Chem (2001), 39(19), 3311-3319. 3. (a) Cherkaoui Z.; Esfandiari P.; Frantz R.; Lagref J.-J.; Liska R. W02012126695 (A1) (b) Esfandiari P.; Ligon S. C.; Cherkaoui Z.; Frantz R.; Lagref J.-J.; Liska R. Macromol. Rapid Comm. 2013 submitted. 4. B. Husaar, R. Liska; Chem Soc Rev 2012;41(6):2395-2405 5. C. Heller, M. Schwentenwein, G. Russmuller, T. Koch, D. Moser, C. Schopper, F. Varga, J. Stampfl, R. Liska: J Polym Sci, Polym Chem 49 (2011), 3; 650 - 661. 6. A. Mautner, X. Qin, B. Kapeller, G. Russmueller, T. Koch, J. Stampfl, R. Liska, Macromol. Rapid Comm., 2012, in print DOI: 10.1002/marc.201200502 7. http://www.bbc.co.uk/news/technology-17357374 Alessandro Pellis (1 ) , Livia Corici (2 ) , Valerio Ferrario (1 ), Cynthia Ebert (1 ) and Lucia Gardossi (1)* (1) Dipartimento di Scienze Chimiche e Farmaceutiche, Universita degli Studi di Trieste, Piazzale Europa 1, 34127 Trieste, Italy (2) SPRIN S.p.A., via Flavia 23/1, 34148 Trieste, Italy *gardossi@units.it The extraordinary catalytic potential of enzymes and lipases in particular in polyesters synthesis has been reported in the last two decades.[1] Enzymes are selective bio-catalysts that enable the minimization of protection/deprotection strategies so that monomers with functionalities can be used while avoiding branching. The benefits coming from the use of enzymes in polycondensation reactions are also related to their sustainability and high efficiency at mild conditions: toxic metal catalysts can be avoided and processes can be carried out at temperatures below 80°C. Although the Mn of products attainable by enzymatic polycondensation is in most cases below 10.000, the technology can be used in the production of pre-polymers or in combination with chemical or thermal polymerization. Thanks to the mild reaction conditions, the enzymatic approach to polycondensation is complementary to the chemical synthesis providing a route for the introduction of functional groups inside the polymeric chain with the aim of production of "reactive" polyesters. However, the wide array of enzymatic polyester synthesis described in the scientific literature at laboratory scale are currently not exploited at industrial scale, especially because of low biocatalyst efficiency under process conditions. Recyclability, stability in the viscous conditions of polymerization process and under stirring are the main problems investigated by the "Laboratory of Applied and Computational Biocatalysis" of the University of Trieste. Results achieved in our recent studies will be presented, along with specific enzymatic and synthetic methodologies that can be now used in the enzymatic polycondensation of bio-based polyols and diacids. 2. Results and discussion The reactions were performed using a robust immobilized enzymes suspended in the monomers, without addition of solvent. A specific immobilization method has been developed for preventing the release of the enzyme during the polycondensation into the polymeric product.[2] Lipase B from Candida antarctica (CALB) was used as biocatalyst. KNL 8 Enyzmatic catalysis for polycondensation: Potential impact and technological barriers 1. Introduction O + O Adipic Acid 1,4-Butanediol CalB O Oligomer O Figure 1: An example of polycondensation catalyzed by Lipase B from Candida antarctica (CALB) BLED, SLOVENIA, 3-5 APRIL, 2013 Different oligomers were obtained starting from di-acids and corresponding diesters. The synthesis of functionalized polymers has been also evaluated, by using monomers having different active functional groups as side chain. The effect of reaction conditions on enzyme activity and stability was investigated. In order to control the thermodynamics of the reaction and to improve the kinetics, the polycondensation process was designed in such a way that the reaction mixture forms a thin film. The procedure leads to optimal mass transfer, easy removal of co-products (alcohol or water) and no need of mechanical stirring. The latter factor is of major importance for avoiding damage or grinding of the solid biocatalyst that must be recycled. 3. Conclusions The study reports an analysis of the potential of biocatalysed synthesis to complement chemical routes for the production of functionalized polymers. New immobilization methods and reaction configurations were developed to overcome the barriers that still hamper the implementation of enzymatic polycondensation at industrial level. Acknowledgement Livia Corici gratefully acknowledges European Commission (FP7, People) for a fellowship (REFINE project). [1] R.A. Gross, M Ganesh, W. Lu, Trends Biotechnol, 2010, 28, 436-443. [2] V. Ferrario, C. Ebert L. Knapic, D. Fattor, A. Basso, P. Spizzo, L. Gardossi. Adv. Synth. Catal. 2011, 353, 2466 - 2480 KNL 9 Scanning force microscopy beyond imaging: determine polymer properties on the nm-scale Sabine Hild* Johannes Kepler University, Institute of Polymer Science, Altenberger Strasse 69, 4040, Linz, Austria *sabine.hild@jku.at 1. Introduction The development of advanced polymers and polymer based composite materials requires detailed information about the physical and chemical properties. Analysis techniques such as differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and dynamical mechanical analysis (DMA) are important and reliable instruments in polymeric research, however, up to now mainly bulk properties are detected. Polymeric materials are often heterogeneous on nanometer scale and composition as well as heterogeneity can vary due to processing. Since polymer microstructure, material properties and processing conditions are linked the thermal or mechanical characterization on a microscopic scale and the visualization of morphology have to be carried out simultaneously. Scanning force microscopy (SFM) has proven to represent a suitable method to fulfill this task. Dynamic imaging techniques such as Tapping mode and phase imaging have been widely explored as a tool for morphology characterization allowing the in-situ monitoring of deformation or thermal induced changes in polymer microstructure. The high spatial resolution of this technique can also be combined with the characterization capabilities of mechanical and thermal analysis. Thus, it is possible to directly measure the mechanical and thermal responds of a specimen in a localized region rather than on the macroscopic scale. Thereby on inhomogeneous samples the material properties can be mapped and determined for different phases on the sub-|im scale. 2. Nanomechanical characterization On macroscopic scale nanoindentation provides accurate material properties measurements that can directly be compared to Dynamic Mechanical Analysis (DMA). When the cantilever of a SFM is used as an indenter instead of being scanned laterally across the sample surface nanoindentation experiments can be performed and mechanical properties can determined on the nanometer scale. To use the SFM tip as an instrument for depth sensing the load applied on the tip and the relative motion between tip and sample will be detected recording a force curve, i.e., a plot of penetration depth vs. applied load. Subsequent application of contact mechanics models enables the estimation of mechanical parameters. Besides the high spatial resolution key benefits on using the SFM as a nanoindenter are on one hand that the indented area can be imaged, and the shape and evolution of the indent imprints can be studied as a function of time. On the other hand, a unique versatility in the load range achieved by changing the cantilever stiffness, which can vary between fractions of nN up to a few tens of |N. Nevertheless, some experimental difficulties and calibrations have to taken into account. First of all, since the load is applied through a bending cantilever the traveling distance of the piezo does not directly reflect the indentation depth. For this reason, the deflection of the cantilever has to be calibrated on a hard material to determine the deflection sensitivity. For each probe the cantilever elastic constant has to be taken from producer data or estimated on the basis of approximate methods. Furthermore, for the calculation of mechanical parameter tip curvature radius, or, in some cases the overall tip geometry has to be known. Ussually, this value has been taken from producer data not considering the production scattering or that the tip shape of conventionally used silicon cantilever can change due to mechanical damage or contamination with soft material. To find a remedy well special indentation cantilevers were used in our experiments with calibrated spring constants and square shaped diamond tips. BLED, SLOVENIA, 3-5 APRIL, 2013 Conventional nanoindentation refers to quasi-static indentation testing in the submicrometer range. Additionally, by modulating the force and/or the displacement nanoindentation can be performed in dynanmic (ac) mode. Thus, performing the experiments at variable temperatures quantitative studies of dynamic mechanical properties such as viscoelasticity becomes possible. 3. Nanothermal characterization Thermal analysis have been important and reliable instruments for polymeric research, however, up to now mainly bulk properties are detected. To understand local mechanisms for temperature-induced phase transitions quantitative measurements of the thermomechanical behavior such as glass transition and melting temperatures as well as temperature dependent elastic modulus and thermal expansion coefficients in nanoscale volumes are required. Local thermal analysis (LTA) combines the basic concept of common thermal analysis and the high resolution of scanning probe microscopy to form a novel technique for polymer characterization. In LTA a heatable tip is broad into contact with a polymeric surface and the cantilever deflection is measured as the tip temperature is increased. A sharp deflection of the tip into the material occurs at a specific 'softening temperature' that is presumably related to either the glass transition temperature (TG) or the melting temperature (TM) of the material being tested. In conventional thermomechanical analysis a Wollaston wire based scanning tip have been is used. This system is not suitable for thermal analysis at sub-^m length scales because a 5 ^m diameter wire is bent into a tip with 20 ^m radius of curvature. The development of highly doped Si AFM tip that is resistively heated allows spatially resolved measurement of thermomechanical properties at nanometer length scales, resulting in nano-LTA measurements. Previous nano-LTA observations have led to many contradictory observations, because the 'softening' transition in polymer films is related non-trivially to the supporting solid substrate below the film and to the environment above it by thermal and mechanical couplings. For the quantitative data analysis an appropriate temperature calibration method has to be established, which correlates unambiguously the deflection signal of the measurement with the softening temperature of the probe. However, the interpretation of the softening temperature is complicated by a number of factors, such as the film thickness and the thermal and mechanical properties of the substrate on which the film is supported. An appropriate calibration procedure based on polymer softening temperatures and power applied to the tip will be presented to correlate the results of nano-LTA measurements with results obtained from DSC. 4. Outlook of the talk In the presentation experimental basics of SFM nanoindentation and local thermal analysis (LTA) for polymer characterization on the nanometer scale will be discussed. SFM nanoindentation and local thermal analysis are applied to investiagted the solvent induced changes in the thermal and mechanical properties of polymer coatings and in a close to surface region of bulk materials. The suitability of ac nanoindentation at variable temperatures for the determination of local viscoelasticity will be demonstrated. KNL 10 New synthetic polymers and nanocomposites: From self-directed assembly to semiconductor superhighways Todd Emrick*, Emily Pentzer, Jimmy Lawrence, and Zachariah Page Polymer Science and Engineering Department, University of Massachusetts Amherst, Amherst, MA 01003, United States of America *tsemrick@mail.pse.umass.edu This presentation will describe the synthesis of polymers and nanoparticles, and the combination of polymers and particles into well-organized arrays. These arrays, or 'superhighways', give access to nanostructured hybrid materials that align p-type (hole carrying) and n-type (electron carrying) components. Such materials are potentially ideally suited as active layers in devices, such as solar cells. The presentation will also highlight syntheses of conjugated polymers that possess orthogonal solubility to conventional active layers, such as hydrophilic poly(benzothiadiazoles) that alter the work function of metals when present as thin films on metal surfaces. BLED, SLOVENIA, 3-5 APRIL, 2013 KNL 11 Rechargeable batteries based on Li-sulfur/poly(acrylonitrile ) composite materials: Synthesis and structure-related electrochemistry Jean Fanous (1 ) , Marcus Wegner (1), Jens Grimminger (1 ), Malte Rolff (1 ) , Anne Andresen (1), Abhishek N. Mondal (2 ) , Michael R. Buchmeiser (2) (1) Robert Bosch GmbH, Corporate Sector Research and Advance Engineering, 70049 Stuttgart, Germany (2) Institute of Polymer Chemistry, University of Stuttgart, 70569 Stuttgart, Germany Among the most promising element combinations for the next generation of batteries is lithium/sulfur. Starting from elemental sulfur, i.e. from S8, the electrochemical reduction cascade finally leads to poly(sulfide)s, Sx2", which are soluble in the chosen electrolyte for at least x<3. Consequently, diffusion of active cathode material, i.e. of poly(sulfide)s to the anode occurs, resulting in the formation of Li2S at the lithium surface and a sometimes dramatic loss in capacity. One concept for poly(sulfide) retention is to embed sulfur inside a cyclized poly(acrylonitrile) (PAN) structure by heating PAN and elemental sulfur to >300°C.1 In course of this procedure, the sulfur dehydrogenates PAN, which forms cyclic structures with a conjugated n-system. In order to clarify how sulfur is embedded into the cyclic PAN-derived network, different PAN/sulfur composites were synthesized. TOF-SIMS, XPS and FT-IR experiments strongly suggest that in all composites the sulfur is exclusively covalently bound to carbon and not to nitrogen. Moreover, N-C-S- fragments, most probably resulting from 2-pyridylthiolates as well as Sx (x>2) and thioamide fragments, have been identified by TOF-SIMS. A structure for the composite is presented that explains for all analytical data as well as for the entire electrochemistry observed. A sulfur balance carefully established during discharge strongly suggests that the polymer backbone, which most probably consists of a conjugated n-system, significantly contributes to the initially measured capacity. Finally, issued concerning the Li-anode will be addressed. 1. J. Wang; J. Yang; J. Xie; X. Naixin. Adv. Mater. 2002 (14) 963. 2. J. Fanous, M. Wegner, J. Grimminger, A. Andresen, M.R. Buchmeiser Chem. Mater. 2011 (23) 5024. 3. J. Fanous, M. Wegner, J. Grimminger, M. Rolff, M.B.M. Spera, M. Tenzer and M.R. Buchmeiser, J. Mater. Chem. 2012, in press. KNL 12 New ways for the characterization of appearance properties of plastic products and components close to human vision Dieter P. Gruber (1)*, Gerald R. Berger (2 ), Walter Friesenbichler (2 ) (1) Polymer Competence Center Leoben GmbH, Leoben, Austria (2) Montanuniversitaet Leoben, Chair of Injection Molding of Polymers, Leoben, Austria *dieter.gruber@pccl.at 1. Introduction The first impression of a product's quality is formed by the appearance of its surface and in most cases, strong conditioning has produced expectations on specific surface attributes that a certain product has to show. In this respect, the human eye-apparatus is still considered to be the most sophisticated evaluation tool. However, evaluation of surface appearance performed exclusively through human observation proves insufficient since the judgment depends on individual factors like the observer's eyesight, experience and mood at the time of the evaluation. Consequently, there is a strong demand for measurement techniques which provide results that are for one unambiguous and reproducible, but also correspond to the visual perception of individual evaluators. Our newly developed surface inspection methods include the quantitative evaluation of a variety of visual surface deficiencies [1-3]. The methods can be translated into practice, e.g. for a better in-depth optimization of injection molding and extrusion processes and for IN-LINE quality inspection of extruded or injection molded parts. 2. Measurement For our investigations, a multifunctional injection mold was used to manufacture examination samples with controlled defect formation. The polymer part includes ribs with varying thickness. The focus of current studies lies in the quantitative evaluation of the visual perceptibility of sink marks caused by ribs at the sample's back side. The main wall thickness of the test part measures 2.5 mm while ribs are 1.2 mm, 1.6 mm, 2.0 mm and 2.5 mm thick (Figure 1). Sink marks are shrinkage related phenomena that depend on processing parameters like mold and melt temperature and holding pressure. In a test series, the holding pressure was varied within a range of 20 MPa to 80 MPa. Other processing parameters like the barrel and mold temperature, as well as the injection rate were kept constant. The used polymer was black polycarbonate (PC). In order to ensure a stationary process, 10 cycles of each setting were discarded. The machine vision system included CCD-cameras and D6500 standard light sources. The light sources were adjusted that way that surface structure showed maximal contrast. Finally, images are captured which form the raw data for the calculation of the perceptibility of the surface defects. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 Figure 1: Backside of an injection molded test part (left) and image of sink marks (right) caused by reinforcing rips 3. Results and discussion Intensity matrices taken from digital images of the regions of interest contain information about shadows, gloss and other visual parameters which form quality deciding aspects. One objective was to derive a model parameter which allows for fast evaluation of the visual perceptibility of any given sink mark. In the first processing step profiles were calculated from the image matrices across the expansion of the sink marks. From these profiles, the second derivative was calculated. For further processing, a polynomial was used to fit the second derivative. The resulting smooth function ensures a fast and robust calculation of higher order derivatives. A high extreme value of the second derivative corresponds to a local low extreme value of the original profile. Hence, the amplitudes of the second derivative tend to form a measure for the magnitude of sink marks. In order to locate the sink marks within the image data, the zero-crossing of the second derivative was determined. It lies necessarily between two zero-crossings of the first derivative. The local extreme values of the second derivative were found between two zero-crossings of the first derivative. These positions do not alter. It became apparent that the amplitude of the second derivative (ASD) is related to a sink mark's visual perceptibility. In order to prove the results of the machine vision system, a panel study was carried out where human evaluators rated the visibility of different sink marks. The assessors were instructed to rate sink marks by using grades between 0 and 10. The highest grade 10 was defined to be mandatory for the visually strongest sink mark in a series. The lowest grade 0 was only to be taken for specimens without a perceptible sink mark. That determination enabled the comparison of the assessments of different evaluators. Figure 2 shows a selection of inspected surface defects. Gloss Weld Lines Sink Marks Moisture Streaks Perception Tensors of Defects 7 7 T frv. y. Figure 2: Selection of characterized surface defect types at an injection molded test parts 5. Conclusions There is a strong industrial demand for automated defect characterization of injection molded polymer parts. For In-Line use, processing has to be fast and the results have to correspond to human vision. A newly developed surface inspection system enables the quantitative evaluation of a variety of different polymer surface defects. In order to quantify the perceptibility of these defects, ASPM 2013 ** AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 a model function was derived. Molded polymer parts, which exhibit sink marks caused by a series of differently pronounced ribs on the back side of the parts, were evaluated. In the processing, profiles of the surfaces were calculated from surface image matrices across the expansion of the sink marks. From these profiles, the second derivative was calculated and fitted to a polynomial. The surface data was captured by the machine vision system and the visual perceptibility of each sink mark was calculated automatically by applying the model function. The results of the machine vision system were compared to results gained in a human assessment study and they turned out to correlate very well to human vision. The method can be translated into practice, e.g. for a better in-depth optimization of injection molding processes and for IN-LINE quality inspection. Acknowledgements The research work of this paper was performed at the Polymer Competence Center Leoben GmbH (PCCL, Austria) within the framework of the COMET-program of the Austrian Ministry of Traffic, Innovation and Technology with contributions by the Chair of Injection Molding of Polymers, Montanuniversitaet Leoben. The PCCL is funded by the Austrian Government and the State Governments of Styria and Upper Austria. References [1] D.P. Gruber, G. Berger, G. Pacher, W. Friesenbichler, Novel approach to the measurement of the visual perceptibility, Polymer Testing, Polymer Testing 30 651-656 ,2011 [2] D.P. Gruber, Neuartige Methode zur Messung der Glanz-Klarheit des Erscheinungsbildes von Werkstoff- und Produktoberflachen, Patent pending, 2011, [3] D.P. Gruber, Method for automatically detecting defects on the surface of a molded part, Patent, 2010, 102319A1 KNL 13 Nanoparticle-polymer hybrid solar cells Gregor Trimmel* Graz University of Technology, Institute for Chemistry and Technology of Materials & Christian Doppler Laboratory for Nanocomposite Solar Cells, Stremayrgasse 9, 8010, Graz, Austria *gregor trimmel@tugraz.at 1. Introduction Organic based solar cells have seen impressive progress during the last 5 years reaching power conversion efficiencies of 10 % [1]. In this presentation, a short introduction of the status quo of polymer based solar cells will be given, focusing then on nanoparticle-polymer hybrid solar cells consisting of both organic semiconductors and inorganic semiconductor nanoparticles. Although the currently obtained power conversion efficiencies are lower (4-5%), this type of material aims at combining the specific advantages of organic semiconductors, like easy processability and high absorption coefficients with the high charge carrier mobilities in inorganic semiconductors [2]. Whereas in classical polymer-fullerene solar cells, the absorption of light is optimized by the absorption properties of the polymer, in hybrid solar cells this can be achieved either by the polymer or the semiconductor nanoparticles. The quantum confinement effects as well as the possibility to use nanoparticles of different shapes (dots, rods, tetrapods, multibranched crystals) lead to unique features of this type of materials. Different synthetic approaches towards nanocomposite solar cells will be discussed in detail. Besides the low thermal stability of conjugated polymers, the main challenge are the different polarity of inorganic nanoparticles and the conjugated polymers requiring synthetic optimisation for both phases and the control of the interface and morphology of the nanocomposite materials. 2. Results and Discussion In the second part, the influence of several synthesis routes on the obtained morphology and purity of the hybrid layers and consequently on the solar cell parameters will be exemplarily discussed. In particular, the in-situ preparation of copper indium sulfide nanoparticles directly in a matrix of the conjugated polymer via the decomposition of metal xanthates at relatively low termperatures yields solar cells with power conversion efficiencies up to 2.8% [3]. Different conjugated polymers based on poly(thiophenes), poly(fluorenes) and alternating copolymers have been used for the preparation of hybrid solar cells. A critical issue for efficient solar cells is to balance the thermal processing temperatures necessary for the complete decomposition of the metal xanthates with the crystallization of the polymer. A schematic representation of the metal xanthate route is shown in Scheme 1. copper and indium xanthates + CulnS2 . polymer , nanoparticles polymer matrix V precursor layer / thermal conversion m Figure 1. Schematic representation of the metal xanthate route to metal sulfide /polymer hybrid layers BLED, SLOVENIA, 3-5 APRIL, 2013 References [1] G. Li, R. Zhu, Y. Yang, Nature Photonics 2012, 6, 153-161. [2] A.J. Moule, L. Chang, C. Thambidurai, R. Vidu, P. Stroeve J. Mater. Chem. 2012, 22, 2351-2368. [3] T. Rath, M. Edler, W. Haas, A. Fischereder, S. Moscher, A. Schenk, R. Trattnig, M. Sezen, G. Mauthner, A. Pein,D. Meischler, K. Bartl, R. Saf, N. Bansal, S. A. Haque, F. Hofer, E. J.W. List, G. Trimmel, Adv. Energ. Mater. 2011, 1, 1046-1050. KNL14 Creating hierarchically porous polymer materials with emulsion templating Peter Krajnc* University of Maribor, Faculty of Chemistry and Chemical Engineering, PolyOrgLab, Smetanova 17, SI-2000, Maribor, Slovenia and Centre of Excellence PoliMaT, Tehnološki park 24, SI-1000, Ljubljana, Slovenia *peter.krajnc@um.si Emulsions with a high volume fraction of droplet phase can be used to template macro pores within a polymer material if the continuous phase contains monomers and the polymer is obtained by curing the emulsion without compromising the emulsion structure. Secondary pores are created between the macro pores during the curing process and the polymer film itself can contain meso and micro pores, depending on the conditions of preparation, crosslinking degree and the solvent used in the continuous phase. The lecture will present latest developments in the field of emulsion templating, present new chemistries and new results of combining emulsion templating with other methods for the preparation of hierarchically porous materials. High internal phase emulsions are known as emulsions containing more than 74,05 vol% of internal phase. By polymerizing the continuous phase, a solid polymer with large pores in place of the droplets of internal phase and a series of interconnecting pores is prepared. Relatively large pore sizes yield material with low surface area. In order to enlarge the surface area, a post-polymerisation hypercrosslinking reaction is possible. Additional linkages are created resulting in smaller pores and higher surface area. In this way a hierarchical porous monolithic polymer can be prepared. A Friedel-Crafts reaction between chloromethyl groups in the polymer matrix can be utilized for post-polymerisation crosslinking approach (Figure 1). The reaction is processed via Friedel-Craft catalyst and the amount of chloromethylated groups reacting can be controlled by kinetics. A number of mesopores are created which has a dramatic effect on the surface area of the polymer. For example, a 2 % crosslinked vinylbenzyl chloride based polyHIPE, subsequently hypercrosslinked was prepared and an increase of surface area from 5.7 to 990.0 m2/g was found. A substantial amount of chloromethylated groups were left enabling further functionalisation of the polymer. Figure 1. Hypercrosslinking via Friedel-Crafts Reaction Another approach to hypercrosslinking is to utilize the remaining double bonds in the polymer matrix which can react with multifunctional thiols. For this purpose a series of polyHIPE samples with varied crosslinking degree were prepared. Samples were reacted with both 2,2(ethylenedioxy)-diethanethiol and pentaerythritol tetrakis(3-mercaptopropionate) with radical initiator in order to obtain linkages with double bonds via thiol-ene reactions (Figure 2). By using a mixture of 2,2(ethylenedioxy)-diethanethiol and bifunctional alkene, the reaction resulted in significant enlargement of BET surface area, from 107 to 233 m2/g. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 S—R—S \ SH , / I / S—R—S SH Figure 2. Thiol-ene grafting onto STY/DVB polyHIPEs References [1] K. J. Lissant, Emulsions and Emulsion Technology, Part 1, Marcel Dekker, New York, 1974, Chap.1. [2] I. Pulko, P. Krajnc, Macromol. Rapid Commun. 2012, 33, 1731-1746. [3] S. D. Kimmins, N. R. Cameron, Adv. Funct. Mater. 2011, 21, 211-225. [4] N. R. Cameron, P. Krajnc, M. S. Silverstein, Colloidal Templating; in M. S. Silverstein, N. R. Cameron, M. A. Hillmyer (Eds.), Porous Polymers, John Wiley & Sons, Inc., Hoboken, New Jersey, 2011. [5] V. A. Davankov, M. P. Tsyurupa, React. Polym. 1990, 13, 27-42. [6] K. Aleksieva, J. Xu, L. M. Wang, A. Sassi, Z. Pientka, Z. P. Zhang, K. Jerabek, Polymer 2006, 47, 6544-6550. [7] I. Pulko, J. Wall, P. Krajnc, N. R. Cameron, Chem. Eur. J. 2010, 16, 2350-2354. [8] C. E. Hoyle, C. N. Bowman, Angew. Chem. Int. Ed. 2010, 49, 1540-1573. KNL 15 Synthesis of functionalized PLA and PLGA Coleen Pugh*, Abhishek Banerjee, Colin Wright, Xiang Yan, Peiyao Wang, Jialu Yan, William Storms The University of Akron, Department of Polymer Science, 170 University Ave., Akron, OH, USA *cpugh@uakron.edu 1. Introduction Polyesters of lactic acid (PLA), glycolic acid (PGA) and their copolymers (PLGA) are the most commonly used materials for biomedical, and disposable or non-recoverable polymer goods applications because they degrade under biological and environmental conditions; their degradation products occur naturally in the body and the environment; and their monomers are naturally derived. We recently designed and synthesized acrylate inimers that produced the first truly hyperbranched analogs of linear polyacrylates upon homopolymerization by atom transfer radical polymerization.1 The key intermediate of this new class of inimers is a 2-halo-3-hydroxypropionic acid (halo = Cl or Br), which we synthesize regioselectively starting from serine,2 a natural amino acid that can be isolated from soybean protein. Since 2-halo-3-hydroxypropionic acids are halogenated isomers of lactic acid, yet have a primary alcohol group like glycolic acid, we believe they are ideal comonomers to copolymerize with glycolic acid and/or lactic acid to provide PLA and PLGA with sites for attaching biologically active or other functional molecules.2 The aim of this research is to establish the synthesis and properties of halogenated PLAs and PLGAs, and their functionalization reactions based on the bromine substituent. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 C3H5XO3 X = Cl, Br X 1A^OH C^ |actic acid -^ ho O O O HO^^^ C2H4O3 glycolic acid Figure 1. Synthesis of hyperbranched polyacrylates and halogenated polyesters based on 2-halo-3-hydroxypropionic acid Sample Feed Ratio LA : GA: BrA Yield (%) Mn x 10 DPn pdi Tg (oC) PLA 100 : 0 : 0 54 3.16 439 1.62 51 PLGBrA502030 50 : 20: 30 70 1.89 203 3.86 39 PLBA5050 50 : 0 : 50 44 2.03 182 1.93 35 Table 1. Acid Catalyzed "Bulk" Copolyesterification of 2-Bromo-3-hydroxypropionic Acid at 95 oC in Vacuo for 48 h. 2. Results and discussion Table 1 presents the p-toluenesulfonic acid catalyzed copolyesterification results of 2-bromo-3-hydroxypropionic acid (BrA) with glycolic and/or lactic acid on a 1 g scale. Although both GA and BrA decrease the molecular weight (according to GPC relative to linear polystyrene) of the copolymers relative to homopolymerization of LA, it Is possible to generate brominated polymers in the 20 kDa range. Both GA and BrA also decrease the glass transition temperatures slightly. We will elaborate on these results, as well as present various functionalization reactions. 3. Conclusions Relatively high molecular weight (Mn ~ 20 kDa) halogenated PLAs and PLGAs can be synthesized by polyesterification. These halogenated polymers can be functionalized through nucleophilic substitution and radical reactions. Acknowledgements We gratefully acknowledge partial funding by NSF (DMR-0630301), NIH (ARRA Supplement for GM86895-2), and Omnova Solutions. References [1] (a) C. Pugh, A. Singh, A. "Synthesis of Inimers and Hyperbranched Polymers", W02008045299-A1; EP2079844-A1; IN200902573-P1; CA2665607-A1; CN101553571-A; JP2010506000-W, April 17, 2008. (b) C. Pugh, A. Singh, R. Samuel, K.M. Bernal Ramos, K.M. Macromolecules 2010, 43, 5222-5232. [2] Pugh, C.; Raveendra, B.; Singh, A.; Samuel, R.; Garcia, G. SynLett 2010, 1947-1950. [3] Pugh, C.; Banerjee, A.; Storms, W; Wright, C.. "Functional Biodegradable Polyesters", UAkron 810, U.S. Patent Application 61/368413, filed on July 28, 2011. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 KNL 16 Zwitterionic polymers: kinetics, characterization and biomedical applications Peter Kasak (1,2 ) , Patrik Sobolčiak (1) , Vladislav Semak (1) , Marek Stach (1) , Zuzana Kronekova (1) , Gabriela Kollarikova (1 ) , Igor Krupa (1,2 ) , Dušan Chorvat (3 ) , Igor Lacfk (1 ) (1) Polymer Institute SAS, Department for Biomaterials Research, Dubravska cesta 9, 845 41 Bratislava, Slovakia (2) Current address: Center for Advanced Materials, Qatar University, P.O. Box 2713, Doha, Qatar (3) International Laser Centre, Department of Biophotonics, Ilkovicova 3, 841 04 Bratislava, Slovakia 1. Introduction Zwitterionic polymers have been intensively studied owing to their suitability for the design of non-biofouling materials and surfaces with unique physical and chemical properties [1,2]. Polyzwitterions are built of electrically neutral monomer units formally containing both positive and negative charges on different atoms in a monomer unit. The monomer units are represented by various chemical structures such as sulfobetaines, carboxybetaines and phosphorylbetaines. This contribution will highlight our recent activities in the areas of synthesis, characterization and application of zwitterionic polymers and hydrogels. 2. Results and discussion The synthesis of zwitterionic polymers is so far lacking a detailed description of mechanism and kinetics of polymerization. Our experience in this area, specifically related to the free-radical polymerization kinetics and mechanism of water-soluble monomers polymerized in aqueous solutions [3], was recently applied for the kinetic studies of sulfobetaine monomers [4]. By employing the pulsed-laser polymerization in conjunction with the size-exclusion chromatography, the first propagation rate coefficients, kp, were determined. The Arrhenius parameters characterizing kp and the solvent effect manifested by the kp decrease with increased monomer concentration were of similar range than those for partially neutralized methacrylic acid [3]. The increase in kp values was observed in the presence of simple salt due to the anti-polyelectrolyte effect. Sulfobetaine hydrogels of various characteristics were prepared by free-radical polymerization in the presence of newly synthesized zwitterionic crosslinkers [5]. These crosslinkers were used in order to suppress the compositional drift during the hydrogel formation. Hydrogels crosslinked using different crosslinking conditions were characterized in terms of mechanical properties, degree of crosslinking, equilibrium water content, sorption degree, diffusion coefficient of water, state of water and attachement of fibroblast cells. Zwitterionic hydrogels were successfully applied as the immobilization matrix for functional entrapment of the glucose-binding protein, which was used for sensing the glucose level in the design of implantable glucose biosensor. Zwitterionic polymers and hydrogels were tested in several other areas. Electrografting of sulfobetaine polymers to the conductive surface resulted in highly reduced biofouling tested by fibroblast cells [6]. In addition, the photo-induced coating made of sulfo- and carboxybetaines was used to modify the surface of various polymeric substrates. Recently we proposed the novel cationic copolymer that is light-switchable to the zwitterionic carboxybetaine [7]. This principle was demonstrated in the capture and release, upon illumination, of DNA as well as on light-switching from antibacterial to non-toxic surface characteristics (Figure 1). Finally, the preliminary data on application of zwitterionic polymers in the design of microcapsules aimed at immunoprotection of transplanted cells will be shown. Figure 1. Light-switchable polymer from cationic to carboxybetaine forms for controlling the interactions with DNA and bacterial cells. 3. Conclusions The group of zwitterionic polymers is a pleasant "playground" with numerous opportunities for studies in macromolecular chemistry as well as at the border between macromolecular chemistry and biological sciences. The outcomes from our work represent a new knowledge in the kinetics and mechanism of polymerization, which should continue towards the complete kinetic scheme and modeling of polymerization, and exemplifies a few from a number of possibilities, where zwitterionic polymers are advantageous in controlling the interaction with biological compounds. Acknowledgements This work has been financially supported by the Slovak Research and Development Agency under the contracts No. APVV-0486-10, by VEGA Grant Agency under the contract No. 2/0160/12, the EFSD New Horizons grant and the Sixth Framework Program of the EU, IP-031867, P. Cezanne. BLED, SLOVENIA, 3-5 APRIL, 2013 References [1] A. B. Lowe, C. L. McCormick, Polyelectrolytes and polyzwitterions: synthesis, properties, and applications, ACS Books, Washington DC, 2006. [2] A. J. Keefe, S. Jiang, S. Nature Chem. 2012, 4, 59-63. [3] I. Lacik, L. Učnova, S. Kukučkova, M. Buback, P. Hesse, S. Beuermann, Macromolecules 2009, 42, 7753-7761. [4] P. Sobolčiak, P. Kasak, M. Stach, D. Chorvat, I. Lacik, prepared for publication. [5] P. Kasak, Z. Kronekova, I. Krupa, I. Lacik, Polymer 2011, 52, 3011-3020. [6] M. Stach, Z. Kronekova, P. Kasak, J. Kollar, M. Pentrak, M. Mičušik, D. Chorvat T. S. Nunneyd, I. Lacik, Appl. Surf. Sci. 2011, 257, 10795-10801. [7] P. Sobolčiak, M. Špirek, J. Katrlik, P. Gemeiner, I. Lacik, P. Kasak, Macromol. Rapid Commun. 2013, early view DOI: 10.1002/marc.201200823 AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 LECTURES Session 1: Advances in Polymer Synthesis and Modification S1-L1 Covalent modification of unsaturated polymers using iEDDA click chemistry Astrid-Caroline Knall (1 )*, Sebastijan Kovačič, Christian Slugovc (1) Institute for Chemistry and Technology of Materials (ICTM), Graz University of Technology, Stremayrgasse 9/V, A-8010 Graz, Austria *a.knall@TUGraz.at 1. Introduction The inverse-electron demand Diels-Alder addition between tetrazines and alkenes (Figure 1) has been recently applied for the conjugation of functional materials, especially in life sciences (due to its bioorthogonal nature) [1]. Tetrazines act here as electron-deficient dienes, whereas the dienophile should be electron-rich. The bicyclic Diels-Alder adduct decomposes upon elimination of nitrogen, and the resulting dihydropyridazine intermediate is then oxidized to the final pyridazine product. Other driving forces are ring strain and a low degree of sterical hindrance [2]. Recently, this new concept for click chemistry has also gained attention in the polymer science community as a facile method for polymer modification and the preparation of block copolymers [3]. I " ii i N^N Rl Figure 1. iEDDA click chemistry 2. Experimental Screening experiments (Table 1): Equimolar amounts of the respective alkene and tetrazine (3,6-diphenyl- and 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine) were mixed in dichloromethane at room temperature. Reaction progress was monitored visually and by TLC and reactions were stopped after full turnover by evaporating the solvent. The solid residue was taken up in CDCl3 and conversion was determined by 1H NMR spectroscopy using the tetrazine peaks in the region of 9 to 7.5 ppm (for py-Tz) and the peaks of the formed (dihydro)pyridazine products. Kinetic measurements of iEDDA reactions in methanol (Figure 2) were performed by monitoring the characteristic tetrazine absorption maximum at 545 nm using different molar (excess) ratios of tetrazines and alkenes under pseudo first-order conditions. A tetrazine starting concentration of 1 mmol/l was used in all experiments whereas 10, 14, 16 and 20 equivalents of the respective alkene were added. All experiments were repeated three times. ( 3. Results and discussion In Table 1, results for pre-screening experiments are presented. It is evident that for a successful click reaction, electron-withdrawing groups need to be present at the tetrazine ring. Cyclopentene and DCPD both undergo an iEDDA reaction, treatment of DCPD with two equivalents of tetrazine resulted only in partial labeling of the cyclopentene double bonds, most likely due to sterical hindrance. Table 1. NMR pre-studies tetrazine alkene Time Tz Conversion* ph-Tz 1 24h No reaction ph-Tz 2a 24h No reaction py-Tz 1 24h >99%** py-Tz 2a 24h >99% py-Tz 3 24h 61% py-Tz 4 12h >99% py-Tz 5 24h No reaction py-Tz 6 24h No reaction on x=/ N=N ph-Tz N-N '/ % N=N py-Tz -N \V \J ,N=\ i // 2a R=COOMe 2b R=H H O o— "determined by NMR spectroscopy **the strained norbornene double bond is preferred While strained, electron-rich double bonds can be converted using iEDDA chemistry, no reaction products were detected when 5 and 6 were reacted with py-Tz, which are examples of typical substrates for Michael thiol-ene and copper-free azide-alkyne click chemistry. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 Furthermore, reaction constants for different labeling experiments were determined and are shown in Figure 2. The reaction rate for cyclopentene was around one order of magnitude lower than for norbornene reflecting the lower amount of ring strain. The lower reaction rate obtained for DCPD can be explained due to steric crowding of the double bond. 0.0035 0.00300.00250) ■fS 0.0020- I 0.0015-O TO 0.00100) 0.00050.0000 A 1 (0.15 mV) □ 2a (0.10 mV) O 4 (0.015 M's'1) o p. -© 0.010 0.015 0.020 c (alkene) [M] 0.025 cross-linking via olefin metathesis P) ... polymer chain Figure 2. a) Reaction constants of different labeling experiments: norbornene-py-Tz, DCPD-py-Tz, cyclopentene-py-Tz b) structure of poly(dicyclopentadiene) Bulk ring-opening metathesis polymerization of 1 leads to polyDCPD, a tough, rigid, thermoset polymer exhibiting high impact resistance, high chemical corrosion resistance and high heat deflection temperature [4]. During the polymerization, the less strained cyclopentene double bond of 1 is partially converted which creates crosslinking (Figure 2b). This approach was recently used for the preparation of polymerized high-internal phase emulsions (poly-HIPEs) [5,6]. Also, derivatization of the double bonds of these DCPD polyHIPEs using thiol-ene chemistry was demonstrated [6]. Consequently, the remaining strained cyclopentene double bonds could be utilized for iEDDA derivatization as indicated by our preliminary results. 4. Conclusions Different strained and electron-rich olefins were screened for their ability to act as dienophiles in inverse-electron demand Diels Alder reactions with 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine. Currently, investigations are underway to perform iEDDA click chemistry on various polymers with incorporated strained or electron-rich olefins where we focus on orthogonality to other click reactions and materials with inherently reactive double bonds. Acknowledgements A-C.K thanks the Austrian Fonds zur Forderung der Wissenschaften (FWF) for a Hertha-Firnberg fellowship (T-578-19). Financial support of the European Community (CP-FP 211468-2 EUMET), the Oesterreichischer Austauschdienst and the Slovenian Research Agency (OEAD, Project SI 22/2011) is gratefully acknowledged. Christoph Schlogl, Julia Wappel, Manuel Hollauf and Alexander Eibel are acknowledged for their skillful work. References [1] a) M. L. Blackman, M. Royzen, J. M. Fox, J. Am. Chem. Soc. 2008, 130, 13518-13519. b) H. S. Han, N. K. Devaraj, J. Lee, S. A. Hilderbrand, R. Weissleder, M. G. Bawendi, J. Am. Chem. Soc. 2010, 132, 7838-7839. [2] a) F. Thalhammer, U. Wallfahrer, J. Sauer, Tetrahedron Lett. 31, 6851-6854. b) A. Meier, J. Sauer, Tetrahedron Lett., 1990, 31, 6855-6858. [3] a) C. F. Hansell, R. K. O'Reilly, ACS Macro Lett. 2012, 1, 896-901. b) I. A. Barker, D. J. Hall, C. F. Hansell, Claire F. Du Prez, R. K. O'Reilly, A. P. Dove, Macromol. Rapid Commun. 2011, 32, 1362-1366. c)R. J. Williams, I. A. Barker, R. K. O'Reilly, A. P. Dove, ACS Macro Lett. 2012, 1, 1285-1290. [4] J. C. Mol, J. Mol. Catal. A: Chem. 2004, 213, 39-45. [5] a) S. Kovačič, K. Jerabek, P. Krajnc, C. Slugovc, C. Polym. Chem. 2012, 3, 325-328. b) S. Kovačič, N. B. Matsko, K. Jerabek, P. Krajnc, C. Slugovc, C. J. Mater. Chem. A 2013, in press. [6] S. Kovačič , P. Krajnc, C. Slugovc, Chem. Commun. 2010, 46, 7504-7506. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED. SLOVENIA. 3-5 APRIL. 2013 S1-L2 Preparation and characterization of NIR-absorbing polyolefins Patrick Knaack*, Meng Xiaoyan, Simone Knaus Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna * Patrick.knaack@ias.tuwien.ac.at 1. Introduction NIR-absorbing dyes have several broad and rapidly expanding fields of applications. One of these fields in polymer engineering are manufacturing techniques like laser welding and laser cutting. These techniques use IR-Laser (Diode, NdYAG, C02 laser) to bring the necessary thermal energy in the material. This works pretty well for polyamides (e.g. PA12) and some others, but, due to the fact that they are rather IR-transparent, not for polyolefins. Therefore, NIR-absorbers, like graphite, nanomaterials or organic dyes, are needed. Because of their extraordinary non polar character polyolefins are a challenge as substrates for dyes, which are often polar or possibly even ionic substances due to their donor/acceptor architecture. To avoid separation, agglomeration or migration and therefore possible elution of the NIR-absorber we wade from two sides into the problem. At first, we searched for a NIR-absorbing dye with an as non-polar as possible molecular architecture. On the other hand we modified polyolefins with epoxy-functionalities to realize a covalent bonding of the dye to the polyolefin surface. [1] 2. Results and discussion The aim of our work was to immobilize a non-polar functional NIR-absorber onto epoxy-functionalized polyolefin surfaces. We are working with perylenes as chromophore which stands out due to their thermal and bleaching stability and their non polar behavior. If they are fused with anthraquinones, they show a broad and intensive absorption band in the NIR. The slightly modified four step synthesis for the perylene-based dye 1 (Figure la) follows the literature [2] and gives an overall yield of 34%. The nucleophilicity of the amino group and, therefore, its accessibility and reactivity towards the epoxy functionality is enhanced by the introduction of an aliphatic spacer. -o O. r,—\ r,—r,—\ .O 1 R= -NH, or -spacer-NH, Figure 1. a) anthraquinone fused perylene dye b) epoxy-functionalized PP Epoxy-functionalization of the polyolefins (Figure lb) was achieved by melt-grafting in a mini-extruder. As monomers commercially available glycidylmethacrylate or, to hold the mechanical properties of the modified polyolefin at the high level of the virgin material, epoxy-monomeres containing long-chain aliphatic spacers were used [3]. The latter should lead us to materials with good mechanical properties, which have the distinction of being easily processible and achievable for laser manipulation without the drawbacks of common NIR-absorbers. The epoxy groups on the polyolefin surface were used to immobilize the amino functionalized NIR-absorbers. The reaction of different amino functionalities (more or less sterically hindered aromatic amines, depending where in the dye the amino-functionality is introduced and aliphatic amines for the case of an introduced spacer) and the different epoxy moieties was investigated by several model reactions to ensure a high turnover even if the electronic and/or steric requirements are not at their optimum. Therein chloroform and toluene at 60°C show the best results (complete conversion in 6 hours). Latest results of characterization of the NIR-absorber-functionalized polyolefins will be presented. References [1] S. Becker Dissertation (Monomere und polymere Rylenfarbstoffe als funktionelle Materialien), Johannes Gutenberg-Universitat, Mainz 2000. [2] S. Becker Dissertation (Monomere und polymere Rylenfarbstoffe als funktionelle Materialien), Johannes Gutenberg-Universitat, Mainz 2000. [3] K. Schubel Performance Polymers, EVONIKindustries, Marl 2008 BLED, SLOVENIA, 3-5 APRIL, 2013 S1-L3 Sensor dyes for covalent immobilization to polymers, nanoparticles and textiles Gerhard J. Mohr* JOANNEUM RESEARCH Forschungsgesellschaft mbH - Materials, Steyrergasse 17, A-8010 Graz, Austria *gerhard.mohr@joanneum.at Indicator dyes are widely used for the development of optical chemical sensors. Typically, the indicator dyes are immobilized into polymer materials, similar to well-known pH indicator test strips, and exposed to analyte solutions. Furthermore, sensor devices are built where a polymeric sensor layer is immobilized on top of an optical fiber. The light guided from a light source through the optical fiber to the sensor layer and back to the detector is used to calculate analyte concentrations. Fluorescent nanosensors have recently found increasing interest in medical and biological research because they enable continuous monitoring of analytes in living cells, tissues and microorganisms. Nanosensors are obtained by physical embedding or covalent attachment of fluorescent indicator dyes into organic and inorganic nanoparticles. Polymer nanoparticles have some advantages over conventional marker and indicator dyes in that they are less toxic to biosamples, are less cross-sensitive to proteins and can be tailored to enable ratiometric measurements. These sensor materials and optical sensor devices then may find application in medical research, process control, biotechnology, environmental monitoring and food quality control. However, often the indicator dyes are only physically embedded in the polymer matrix, which causes leaching of the dye and thus instability in signal and sensor performance, and more importantly, contamination of the sample. In order to overcome such limitations, indicator dyes have to be covalently linked to polymer materials and sensor surfaces. Several approaches to the covalent immobilization of indicator dyes on copolymers, nanoparticles and textiles will be presented. Vinylsulfonyl dyes with pH-sensitivity can be immobilised to cellulosic materials, thus giving sensor wound dressings and sensor textiles [1]. Methacrylate derivatives of indicator dyes with sensitivity to aliphatic amines are copolymerized with methyl and butyl methacrylates to give sensor layers for continuous monitoring of amines [2,3]. Functional indicator dyes sensitive to pH, fructose and ATP are immobilized within silica nanoparticles via trimethoxysilyl functions [3-6]. All of these sensor materials are characterized for their colour and fluorescence changes as well as sensitivity, reversibility and selectivity towards the analytes. References [1] S. Trupp, M. Alberti, T. Carofiglio, E. Lubian, H. Lehmann, R. Heuermann, E. Yacoub-George, K. Bock, G. J. Mohr, Development of pH sensitive indicator dyes for the preparation of micropatterned optical sensor layers, Sensors and Actuators B, 2010, 150, 206-210. [2] G. J. Mohr, N. Tirelli, U. E. Spichiger, Plasticizer-free optode membranes for dissolved amines based on copolymers from alkyl methacrylates and the fluoro reactand ETHT 4014, Analytical Chemistry, 1999, 71 1534-1539. [3] G. J. Mohr, N. Tirelli, C. Lohse, U. E. Spichiger, Development of chromogenic copolymers for optical detection of amines, Advanced Materials, 1998, 10, 1353-1357. [4] T. Doussineau, S. Trupp, G. J. Mohr, Ratiometric pH nanosensors based on rhodamine-doped silica nanoparticles functionalized with a naphthalimide derivative, Journal of Colloid and Interface Science, 2009, 339, 266-270. [5] A. J. Moro, J. Schmidt, T. Doussineau, A. Lapresta-Fernandez, J. Wegener, G. J. Mohr, Surface-functionalized fluorescent silica nanoparticles for the detection of ATP, Chemical Communications, 2011, 47, 6066-6068. [6] T. Doussineau, A. Schulz, A. Lapresta-Fernandez, A. Moro, S. Koersten, S. Trupp, G. J. Mohr, On the design of fluorescent ratiometric nanosensors, Chemistry -A European Journal, 2010, 16, 10290-10299. S1-L4 Kinetic study of single particle gas-phase ethylene homo-polymerization with Ziegler-Natta catalyst Leonhard Mayrhofer (1 )*, Ravindra R. Tupe (2), Christian Paulik (3 ) (1) Kompetenzzentrum Holz GmbH, Altenberger Strasse 69, 4040 Linz, Austria (2) Process Development Group, Borealis Polymers Oy, P.O. Box330 Porvoo, Finland (3) Johannes Kepler University, Institute of Chemical Technology of Organic Materials, AltenbergerstraGe 69, 4040 Linz, Austria *l.mayrhofer@kplus-wood.at 1. Introduction The main objective of the present study is to understand the kinetic behavior of Ziegler-Natta (ZN) catalyst systems at particle level during gas-phase ethylene homo-polymerization. Video microscopy of growing polymer particles at near industrial conditions was used for studying the kinetic characteristics of the catalyst. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 2. Theory Nearly 50 years after Nobel Prize in chemistry for K. Ziegler and G. Natta for their breakthrough works on transition metal catalyzed polymerizations, these processes are still contributing >70 % [1] to the world production (~235 Mtons in 2011) [2] of plastics. Nowadays the enhancement of polymers (e.g. in reactor blending) plays an important role for advanced polymer solutions [3]. The group of Pater et al. [4] showed that a micro-reactor is a very useful tool to study the kinetics of a growing polymer particle. 3. Experimental The concept of using a micro-reactor for studying the polymerization of a single particle at near-industrial conditions is demonstrated in the present study. The micro-reactor is equipped with a video microscope for capturing the growth of a catalyst particle and with an infrared camera to sense the surface temperature of the growing catalyst particle during polymerization. Conditions used during the experiments are reaction temperatures in the range of 40 to 85 °C and maximum ethylene pressures of 20 bar. A commercial ZN catalyst was used for the gas phase homo-polymerization with ethylene. Triethylaluminium (TEA) was used for scavenging and as co-catalyst. After 30 minutes of pre-contacting, few activated catalyst particles were placed on a polymerization platelet. 5 |L TEA was added next to the polymerization platelet in order to scavenge any present impurities or catalyst poisons. 4. Results and discussion 3,5 _ 3,0 tS 2,5 O ro „ „ uj 2,0 Q_ Js 1,5 O^ 1,0 0,5 0,0 (a) 0 5 10 15 20 25 30 Time (min) 3,5 _ 3,0 ^ 2,5 O s 2,0 Q_ Jg 1,5 Q: 1,0 0,5 0,0 (b) A*' —i-1-1-1-1— 0 5 10 15 20 25 30 Time (min) Figure 01: Polymerization rate (Rp) as function of time at following conditions: (a) 40 °C and (b ) 70 °C, respectively, with 20 bar(a) of ethylene pressure (▲ Average of fastest growth; ■ Average of medium growth; ♦ Average of slowest growth) The obtained results show the complexity with respect to the ZN catalyst based olefin polymerization. It appears that at particle-scale, different polymerization rates can be expected for different particles. This can be associated to a different fragmentation behavior of the individual particles giving access of the necessary monomer to the active sites, which in turn determines the particle growth. Other factors which influence the fragmentation behavior, hence polymerization kinetics, are mass and heat transfer resistances, different active sites as well as the distribution of active sites within the catalyst particle [5]. The importance of particle fragmentation behavior and its influence of the polymerization kinetics are very well summarized by McKenna et al. [1]. Further studies will focus more on evaluating the impact of different process variables on particle fragmentation behavior, and accordingly on polymerization kinetics. 5. Conclusions The micro-reactor experiments exhibited the influence of reaction parameters on the growth of different catalyst particles. The single particle growth kinetic is obtained by processing the visual images, using video microscope during the entire polymerization time. In addition the growth rate estimated based on the increasing volume of growing particles is evaluated to understand the kinetic behavior of this catalyst system at a particle level for different process parameters. Acknowledgements The authors thank Borealis for financial and intellectual support. References [1] McKenna T. F. L. et al., Catalytic olefin polymerization at short times: using specially adapted reactors, The Can. Jour. of Chem. Engg., 2012, 9999. [2] Plastics Europe, www.plasticseurope.org, Plastics-the facts 2012, Page 8 BLED, SLOVENIA, 3-5 APRIL, 2013 [4] Pater, J. T. M., Weickert, G., Swaaij van, W. P. M., Optical and infrared imaging of growing polyolefin particles, AIChE Journal, 2003, 49(2), 450-464 [3] Ruff M., Paulik C., Controlling Polyolefin Properties by In-Reactor Blending, 1-Polymerization Process, Precise Kinetics, and Molecular Properties of UHMW-PE Polymers, Macromolecular Reaction Engineering (2012) 6 (8), pp. 302-317. [5] Ferrari, D., Videomikroskopische Einzelkornanalyse der Olefinhomo- und Copolymerisation mit heterogenen Katalysatoren, Ph.D. Thesis, 2005 Session 3: Polymers from Renewable Resources S3-L5 Renewable (waste) material based polyesters as plasticizers for adhesives Matjaž Kunaver (1,2 )*, Edita Jasiukaityte-Grojzdek (1,2), Dolores Kukanja (1,3 ) , Darko Moderc (1,3 ) (1) Center of Excellence PoliMaT, Tehnološki park 24, 1000 Ljubljana, Slovenia (2) National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia (3) Mitol, d.d., Partizanska 78, 6210 Sežana, Slovenia *matjaz.kunaver@polimat.si 1. Introduction Liquefaction of the biomass based materials has been considered as an effective method for the utilization of the renewable resources in polymer chemistry. Biomass as a main precursor in the liquefaction reaction can be any kind of lignocellulosic materials; the most common source is different types of wood and wood wastes as well as the lignocellulosic parts of industrial plants and agricultural wastes. The liquefied biomass contains depolymerised products of cellulose, lignin and hemicelluloses. Liquefied biomass has a high reactivity due to a large amount of hydroxylic groups that are present. These functional groups can be used in creation of polyurethanes, polyesters and epoxides after the reaction with epichlorohydrin. Poly(ethylene terephthalate) (PET) plastic packaging is produced in considerable amounts and represents a significant portion of household waste. Depolymerization with ethylene glycol or higher glycols and converting the depolymerised PET into new products such as unsaturated polyesters, polyester polyols and polyurethanes is the most common industrial process used nowadays. The glycolysis proces involves utilzation of small amounts of glycol and some transesterification catalyst such as zinc acetate. Poly(vinyl acetate) (PVAc) adhesives are an important type of thermoplastic adhesive, especially in flooring applications, furniture manufacturing and carpentry. They are ready to use, have a short setting time, and give invisible joints. In order to extend its applicability, the flexibility and plastification of the PVAc is achieved by addition of plasticizer. The increasing demand for more environmental friendly materials causes the intensive investigations into new plasticizers and coalescing agents that improve the PVAc adhesive performance. The aim of presented work was the fully replacement of phthalate based plasticizers with environmental friendly materials. Polyesters synthesized from the liquefied wood (PE-LW) and from depolymerized PET (PE-PET) were used as renewable raw materials and tested as substitutes for plasticizers used in PVAc dispersion adhesives for flooring applications. The prepared PVAc adhesives were evaluated with respect to solids content, viscosity, glass transition temperature (Tg), tensile shear strengths and binding strength of the bondline between two wood specimens. As a reference material the PVAc based on 1,2,3-triacetoxypropane (CL) as plasticizer was used. 2. Experimental 2.1 Liquefaction of wood (LW) and synthesis of polyester from LW (PE-LW) The polyhydroxy alcohol mixture of glycerol (150g) and diethylene glycol (150g), p-toluene sulfonic acid (9g) were placed into the 1000 cm3 three necked glass reactor, equipped with mechanical stirring. The mixture was heated with constant stirring to 180°C. After the wood (100g) was added to the preheated reaction mixture the liquefaction reaction was carried out for 120 min. Afterwards, adipic acid was added. Dibutyl tin oxide (0.1% w/w) was added as the esterification / transesterification catalyst. After the completion of the reaction, when the acid value was reduced to less than 30 mg KOH/g, the reaction mixture was cooled to ambient temperature. The hydroxyl value of the polyester was 334 mgKOH/g. 2.2 Glycolysis of PET waste and synthesis of polyester from depolymerised PET (PE-PET) PET waste flakes (10g) together with (31.25g) of polyethylene glycol (PEG) 400 (molar ratio of PET:PEG 400 = 1:1.5) and transesterification catalyst (0.1% w/w) were added into the reactor. The glycolysis of PET waste was carried out at 220°C over 6h. The reaction mixture was cooled to 190°C and adipic acid (4.12g) was added in two portions. After the completion of the reaction, when the acid value was reduced to less than 5 mg KOH/g, the reaction mixture was cooled to ambient temperature. The resulting polyester was identified as PS-PET. The hydroxyl value was 88 mgKOH/g. 2.3 Adhesive preparation Water based adhesives were prepared from commercially available PVAc dispersion Mekolit H45 (Mitol) used as a binder, calcium carbonate (Calcit) used as a filler and a plasticizer. Commercial plasticizer (CL; 1,2,3-triacetoxypropane), PE-LW and PE-PET were used to prepare adhesives by varying the plasticizer amount from 0 up to 25% (w/w). Thin adhesive films were prepared with BLED. SLOVENIA. 3-5 APRIL. 2013 special stencil on silicon-impregnated paper. Prior the testing, adhesive films were dried for 7 days at 23 ± 2°C and 50 ± 5% relative humidity. 2.4 Methods Thermogravimetrical analysis (TGA) was performed on Metller Toledo TGA/DSC1 apparatus and differential scanning calorimetry (DSC) measurements were performed on a Metller Toledo DSC1 apparatus. Intrinsic viscosity measurements of polyesters were performed using a Brookfield DV-E rotational viscometer according to the International standard (ISO 2555). Tensile strength (N/mm2) and elongation (%) were determined using Zwick/Roell Z 010. Testing was performed using three specimens with the dimensions of 100 mm (length) and 15mm (width). (Modification of the AST M 882-95a standard method) Binding strength (N/mm2; wood-wood) was measured using Zwick 1435 mechanical testing machine. For this purpose three specimens with adhering surface of 2 cm2 were kept under the pressure of 7.5 kg/cm2 for at least 24h. Binding strength was determined after 72h of sample conditioning at room temperature with constant crosshead speed of 50 mm/min. (Modification of the EN 14293:2006 standard method) 4. Results and discussion The influence of different addition of plasticizers on mechanical properties of PVAc adhesives for flooring applications was studied. The highest thermal stability exhibited samples prepared with PE-PET independently from the amount of the added plasticizer. As a result, with the addition of PE-PET up to 25% (w/w), the 5% weight loss temperature (Tdec_5%) was reduced only by 10°C, while due to the addition of PE-LW and CL, Tdec.5o/o was reduced by 90°C and 150°C, respectively. PE-PET and PE-LW are more compatible with the PVAc polymer and they stay with the polymer for a considerably longer time than commercial plasticizer. Increasing amounts of CL and PE-PET in adhesive formulation greatly reduced Tg, while the least affected Tg was determined for the samples prepared with PE-LW. The optimal required viscosity (< 85000 mPas) exhibited adhesives with addition of 5% (w/w) of PE-PET and 20% (w/w) of PE-LW. The dispersion adhesive ductility dependence on the amount of plasticizer in adhesive composition was revealed by examination of the mechanical properties. The increasing amount of the plasticizer in adhesive reduces the tensile strength and accordingly increases elongation. The solid content for all adhesives were measured according to ISO 1625 standard. The weight loss is very intensive in the samples prepared by commercial plasticizer. Both polyesters have higher molar mass and polymer structure and have reduced migration properties. 1 □ r p laitE Ize r Commercial plastff icizer » ofplasticiier »sTpoitCHr Figure 1: The 5% weight loss temperature, glass transition (Tg) temperature and binding strength dependence on the percentage of plasticizer, 5. Conclusions We replaced the commercial plasticizer in a PVAc adhesive with environmental friendly polyesters synthesized from the liquefied wood and from depolymerized PET. TGA analysis showed significant differences between thermal stability of added polyesters and commercial plasticizer. Samples prepared with PE-PET exhibit the highest thermal stability even at the addition of 25%. PE-LW was less stable although still better than commercial plasticizer. PE-PET and PE-LW are more compatible with the PVAc polymer, have higher interactions with it and therefore stay in the mixture for a considerably longer time. The DSC measurements revealed a decrease in glass transition peaks temperature with increasing amounts of CL and PE-PET. The least affected Tg was determined for the samples prepared with PE-LW where the lowest Tg was reached in adhesive with 24.1% of PE-LW addition. Increased content of plasticizer in dispersion adhesive composition tends to reduce wood-wood binding strength. The increased amount of the plasticizer in adhesive reduces the tensile strength and accordingly increases elongation. A significant difference is observed in solid content of adhesive when samples were dried at elevated temperature. While the commercial plasticizer slowly evaporates both polyesters remain in the mixture due to polymer structure which are completely stable at that temperature. The requirements for the parquet adhesives were fulfilled by the compositions containing 5% (w/w) of PE-PET and 20% (w/w) of PE-LW. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 Acknowledgements The authors wish to gratefully acknowledge the support for the presented work received from the Ministry of Higher Education, Science and Technology of the Republic of Slovenia through the contract No. 3211-10-000057 (Center of Excellence for Polymer Materials and Technologies) and for the analysis of products within the Program P2-0145 (National Institute of Chemistry). S3-L6 Lignin polyols - renewable resin compounds Kerstin Wallisch*, Dzanana Dautefendic, Simone Knaus Vienna University of Technology, Institute of Applied Synthetic Chemistry, Getreidemarkt 9, 1060 Vienna, Austria *kerstin.wallisch@ias.tuwien.ac.at 1. Introduction Lignin, the second major component of wood and annual plants, is a highly branched and irregular macromolecule, whose structure based on phenylpropanoic units varies with the vegetable species and the method of isolation. Being an abundant and renewable polymer, much effort has been made in the last decades to modify lignin so that it can be incorporated in polymeric material and thus used in applications of higher value. Oxypropylation of lignin is an established method to overcome technical limitations and adverse effects resulting from the polymeric nature of lignin when directly used for synthesis purposes. It increases the reactivity of lignin's functional groups and improves its solubility and uniformity. Such formed low-cost polyols from renewable resources might be able to replace conventional polyols in the polyurethane industry if they possess a certain viscosity and hydroxyl index. Oxypropylation is always accompanied by homopolymerization of propylene oxide, so that the produced polyols are a mixture of oxypropylated lignin and polypropylene oxide homopolymers. Until now only such mixtures, containing a very low amount of lignin, were tested for the manufacture of polyurethanes. The aim of the present work is to investigate which degree of grafting is necessary to convert lignin into a polyol suitable for such applications with respect to viscosity and hydroxyl index. [1,2] 2. Experimental For synthesis of the polyols two different types of lignin (Alcell lignin and Protobind 2400) were reacted with varying amounts of propylene oxide in a high-pressure reactor at 100°C and purified according to literature (scheme 1) [3]. OH COOH O CH2 CH O H CH3 n CH2 CH CH3 O H n COO O Lignin Lignin KO H autoclave: 100°C/ 15h purification: 1) liquid-liquid extraction (acetonitrile/hexane) removal of homopolymer 2) precipitation in water removal of oligomers COOH H-, | Lignin —OH 7/ KO CH, autoclave: 100°C/ 15h I Lignin \ 1 O-f-CHj-CH-O-^H COO-j-CHj-CH-O-^H CH, purification: 1) liquid-liquid extraction (acetonitrile/hexane) —removal of homopolymer 2) precipitation in water —_ removal of oligomers Scheme 1. Oxypropylation of lignin Oxypropylated lignin was acetylated and 1H-NMR spectra recorded to determine the amount of propylene oxide grafted to lignin and resultant the length of the grafted chains; for calculation of the hydroxyl index the polyols - together with an internal standard - were derivatised with 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane (TMDP) and 31P-NMR spectra were recorded (Scheme 2). Additionally the hydroxyl index was also determined by titration. CH, Lignin 1 f 11 mc2u/ j_0-|_CH2-CH-0-^Ac 25„c/ loo—f-CH—CH —0-}^Ac CH, Ac20/pyridine 24h r Ligninl—Q-[-CH —CH —O-^-H 1oo-^ch2-ch-o^h CH, TMDP CH, °~hcH~cH~°"kpc Lignin| COO—f-CH;-CH—0-1—p' I ^ 'o-V CH, N Scheme 2. Acetylation and phosphitylation of oxypropylated lignin for analytical purposes O CH2 CH O H CH3 n CH2 CH CH3 O H n COO O CH2 CH O Ac CH3 n CH2 CH CH3 O Ac n COO O CH2 CH O P CH3 n OO CH2 CH CH3 O P n COO OO Lignin Lignin Lignin Ac2O/pyridine 25°C/ 24h TMDP Rheological tests were carried out with a plate/plate rheometer. The viscosity was determined not only from the raw polyol mixture, but also from the oxypropylated lignin after removal of the oligomers. BLED, SLOVENIA, 3-5 APRIL, 2013 3. Results and discussion Objective of the present work is to synthesize oxypropylated lignins and evaluate if they are suitable for the manufacture of polyurethanes regarding their viscosity and hydroxyl index in comparison to conventional polyols used for this application. For the synthesis of polyols with different viscosities the molar ratio of lignin to propylene oxide was varied from 1:5 to 1:20. The content of propylene oxide homopolymers was determined by weighing the hexane-soluble fraction after liquid-liquid extraction of the polyol mixture. The lignin polyols were acetylated and 1H-NMR spectra from the derivatives recorded. The length of the grafted side chains was found to be in the range of 1.5-8.5. 31P-NMR spectroscopy after derivatisation with TMDP allows distinguishing between hydroxyl groups of oxypropylated side chains and other aliphatic hydroxyls that remained unreacted. Additionally also the amount of phenolic hydroxyls and carboxylic groups can be determined. So it could be shown that it is possible to synthesize lignin polyols where nearly all functional groups are grafted. The hydroxyl indices were not only determined by titration, a well-established method, but also calculated from results of 31P-NMR spectroscopy, as an alternative technique. Hydroxyl indices obtained from 31P-NMR spectra (100-150) showed a good correlation with results obtained after titration of the hydroxyl groups. Therefore 31P-NMR spectroscopy is an adequate and fast tool for hydroxyl value analysis which, additionally, has the advantage that smaller amounts are needed for the analysis. According to results of Nadji et al. [4] polyols with hydroxyl indices in the range of 100-200 are suitable for rigid polyurethane foams confirming that our lignin polyols can be used for that application. Another important parameter is the viscosity of the polyols which should be lower than about 300 Pa*s for the manufacture of polyurethanes [4]. The investigation of oxypropylation reactions of different lignins showed that the properties of the products depend strongly on the nature of the lignin and the applied molar ratio of lignin and propylene oxide. Rheometer measurements showed that a chain length of more than 4 is needed to obtain a viscosity low enough for polyurethane synthesis, otherwise the oxypropylated lignin has to be used in a mixture with the PPO homopolymer. Acknowledgements Part of this work was done within the frame of the program "Factory of Tomorrow", an initiative of the Austrian Federal Ministery of Transport, Innovation and Technology. References [1] A. Gandini, Macromolecules 2008, 41(24), 9491-9504. [2] C. A. Cateto et al, Industrial & Engineering Chemistry Research 2009, 48, 2583-2589 [3] L. C.-F. Wu and W.G. Glasser, Journal of Applied Polymer Science 1984, 29, 1111-11 [4] H. Nadji et al, Macromolecular Materials and Engineering 2005, 290, 1009-1016 S3-L7 Synthesis of novel polymer-bound antioxidants via ADMET polymerization Stephan Beer*, Oliver Bruggemann Institute of Polymer Chemistry, Johannes Kepler University Linz, Welser Strasse 42, A-4060 Leonding, Austria *stephan.beer@jku.at 1. Introduction The project SolPol-2 [1] targets the development of novel polymeric materials based solar water heating systems including new polymer compounds specifically for solar-thermal applications. The unique conditions in these systems require novel solutions for the stabilization of polymeric materials. A particular problem experienced in the use of polymeric materials for such applications is the leaching of the antioxidant in the high-temperature aqueous environment. Our work focuses on the immobilization of antioxidants in order to develop additives for the long-term stabilization of polyolefins suitable for the construction of solar water heating systems. Several approaches for the immobilization of antioxidants via melt free-radical grafting to polyolefins have been reported. Thereby reactive antioxidants, like maleimide-bound antioxidants [2] or acrylic monomers [3] are applied in the grafting reaction to obtain polyolefin-bound antioxidants. In our work we are investigating the ADMET-polymerization of monomer-bound antioxidants, a new approach for the immobilization of antioxidants. Using fatty acid derivatives as monomers leads to polyolefins with functional groups with a well-defined distribution [4]. The presence of these functional groups allows the coupling of antioxidants to the polymer backbone, which can otherwise only be achieved by free-radical reactions under harsh conditions. In our work the applied monomers are based on plant oils, hence renewable resources are employed. LED, SLOVENIA, 3-5 APRIL, 2013 2. Results and discussion The immobilization of antioxidants was achieved by ADMET-polymerization of different monomer-bound antioxidants. These compounds were produced by the synthesis of a,w-dienes which were then coupled to phenolic antioxidants yielding monomers ready for ADMET-polymerization. The ADMET-polymerization of the antioxidant-bearing monomers was carried out using a Hoveyda-Grubbs 2nd generation catalyst. The obtained polymers were characterized by NMR- and FTIR-spectroscopy. High-temperature GPC was used for the determination of molecular weights. The polymer-bound antioxidants were compounded to non-stabilized polypropylene using a lab extruder. For comparison some compounds were stabilized with the commercially used Irganox 1010. In order to achieve comparable results, adjusted amounts of polymer-bound antioxidants and Irganox 1010 were applied leading to equal concentrations of phenol groups in the different compounds. Finally, DSC was employed to measure the oxidation induction time (OIT) of the obtained products. Compared to non-stabilized polypropylene, the OIT can be significantly enhanced by addition of small amounts of polymer-bound antioxidant. The comparison with Irganox 1010 as a stabilizer shows even more interesting results, since the polymer-bound antioxidant surpasses the stabilization achieved by Irganox 1010 (figure 1). Time / min Figure 1. Sample OIT measurements showing how the addition of polymer-bound antioxidant (dotted line) enhances the oxidation induction time of polypropylene (PP) compared to non-stabilized PP (solid line) and compared to PP stabilized with Irganox 1010 (dashed line) 3. Conclusions A novel route to polymer-bound antioxidants was successfully developed using ADMET-polymerization. The antioxidant activity of the products was confirmed by OIT measurements. Acknowledgements This work was financed by the Austrian Research Promotion Agency (FFG) and the "Klima- und Energiefonds" of the Austrian federal government in line with the program "Neue Energien 2020". NMR measurements were carried out at the Austro-Czech RERI-uasb NMR center which was established with financial support from the European Union through the EFRE INTERREG IV ETC-AT-CZ programme (project M00146, "RERI-uasb"). References [1] R. W. Lang, G. M. Wallner, Public Service Review: European Science & Technology; 2012, 14, 68-69. [2] T. H. Kim, D, R. Oh, Polymer Degradation and Stability 2004, 84, 499-503. [3] S. Al-Malaika, N. Suharty, Polymer Degradation and Stability 1995, 49, 77-89. [4] O. Kreye, T. Toth, M. A. R. Meier, European Journal of Lipid Science and Technology 2011, 113, 31-38. BLED, SLOVENIA, 3-5 APRIL, 2013 S3-L8 Membranes for water-purification based on nano-cellulose Andreas Mautner (1)*, Koonyang Lee (1 ) , Kang Li (2), Alexander Bismarck (1,3 ) (1) Imperial College London, Polymer and Composite Engineering group, London SW7 2AZ, United Kingdom (2) Imperial College London, Department of Chemical Engineering, London SW7 2AZ, United Kingdom (3) University of Vienna, Institute for Materials Chemistry & Research, Wahringer StraRe 42, 1090 Wien, Austria *a.mautner@imperial.ac.uk 1. Introduction Clean water nowadays seems to be commonplace in our part of the world. Nevertheless, the struggle for potable water is an all-day trouble in huge areas of planet earth and with the number of people living on this globe still increasing this problem will become even bigger. By this, the need of, preferably cheap and easy to handle, devices for decentralized industrial and domestic water treatment aiming at the removal of various contaminants is an important task. Moreover, devices such as membranes applied for this purpose should not add to pollution of the environment neither through the production processes of base materials and membranes nor through the disposal of used membranes. 2. Theory Since the purification of water is gaining more and more significance, membranes from renewable resources like cellulose have come into the viewpoint of research interest since there is an almost unlimited stock of base materials that derive from renewable resources and whose disposal through composting is an environmentally friendly process. Of course, cellulose as membrane material is well established, but until now the utilization as membrane for the removal of certain types of contaminants like pesticides or microbial contamination was not a comprehensive success. Thus, the aim of this study is to create cellulose-based membranes featuring special characteristics deriving from extraordinary structures and/or derivatives that lead to specific properties of the final membranes that are necessary in the domain of water purification and removal of challenging pollutants. One base material that can be utilized for this purpose is so-called nanofibrillated cellulose (NFC). NFC can be produced via two approaches: top-down and bottom-up. Through the top-down approach (first reported by Herrick [1] and Turbak [2]) nanofibres are produced by disintegration of (ligno)cellulose biomass, such as wood fibres. During this process, the wood pulp is fed through a high-pressure homogenizer to decrease the size of the fibres to finally reach the nanoscale. NFC produced via the bottom-up approach utilizes the fermentation of low molecular weight sugars using cellulose-producing bacteria, such as from the acetobacter species.[3] 3. Experimental To achieve membranes based on NFC, the surface of NFC has been partly modified to achieve more hydrophobic behavior while maintaining the structure composed of nanowhiskers. Thus, organic acids of different length (from acetic acid to dodecanoic acid) have been grafted onto NFC and membranes produced. To characterize the membranes, the degree of surface substitution (DS) of NFC by organic acids was analyzed with a method based on hydrogen/deuterium exchange, the crystallinity by using XRD, the streaming-Z-potential with an electro kinetic analyzer, the hydrophobicity by performing contact angle measurements, and the thermal stability by means of TGA. To study the MW cut-off, polystyrene standards have been used that were analyzed by GPC before and after passing the membrane. 4. Results and discussion The DS on the surface was around 1.5 which is sufficient since only partly modification was desired. Accordingly, the contact angles increased with increasing length of the grafted acid-residues. Nevertheless, the resulting films exhibit no loss in crystallinity compared to neat NFC, which illustrates that the substitution reaction was restricted to the surface only. The isoelectric point derived from Z-potential measurements was shifted to slightly higher values indicating the loss of acidic OH-groups due to the substitution reaction. The degradation temperature slightly decreased with increasing carbon chain length due to the reduced number of effective hydrogen bonds between NFC nanofibres. Finally, the MW cut-off lies in the region of a few kDa, which demonstrates the ability of performing nanofiltration with these type membranes. 5. Conclusions We have shown that it is possible to produce membranes based on renewable resources without the need of environmentally problematic solvents, which enable the elimination of contaminants in the range of a few kDa. Acknowledgements The authors greatly acknowledge the funding provided by the EU FP7 project NanoSelect. References [1] F.W. Herrick, R.L. Casebier, J.K. Hamilton, K.R. Sandberg; in Sarko, A., (Ed.); Microfibrillated Cellulose: Morphology and Accessibility, Proceedings of 9th Cellulose Conference, Ed. Wiley: New York, 1983; p. 797. [2] A.F. Turbak, F.W. Snyder, K.R. Sandberg; J. Appl. Polym. Sci. Appl. Polym. Symp. 1983, 37, 459-494. [3] D. Klemm, B. Heublein, H.P. Fink, A. Bohn; Angew. Chem., Int. Ed. 2005, 44 (22), 3358-3393. BLED, SLOVENIA, 3-5 APRIL, 2013 S3-L9 Structural rearrangements in amorphous nanometric cellulose model films induced by heat treatment Stefan Spirk (1)*, Tamilselvan Mohan (1 ) , Rupert Kargl (2 ) , Ales Doliska (1 ) , Roland Resel (3 ) , Volker Ribitsch (2 ), Karin Stana-Kleinschek (1 ) (1) University of Maribor, Institute for Engineering Materials & Design, Smetanova Ulica 17, 2000 Maribor, Slovenia (2) University of Graz, Institute of Chemistry, Heinrichstr. 28, 8010 Graz, Austria (3) University of Technology Graz, Institute of Solid State Physics, Petersgasse 17, 8010 Graz, Austria *Stefan_spirk@yahoo.de 1. Introduction Probably, there is hardly any other single material that offers such a wide variety of applications in materials sciences as cellulose, the most abundant polysaccharide on earth. It is used in papers, fibers, textiles, packaging materials, hygienic products and serves as a support material in chromatography and life science applications as well. In addition, nanoscale cellulosic materials such as nanocrystals and nanofibrils have gained more and more attention during the past few years due to their unique mechanical and non-linear optical properties. In addition, cellulose is compatible with many other organic and inorganic materials which facilitates the creation of hybrid materials and nanocomposites exhibiting unique properties such as conductive fibers, papers with printed circuits or flame retardant materials for instance. Although most of the aforementioned applications are influenced and determined by the supramolecular structure of cellulose (e.g. different reactivities of crystalline and amorphous domains for nanocrystal preparation), the interaction behavior of cellulose especially with water molecules is not fully understood. In this context, Lindman and co-workers initiated a discussion about the importance of hydrophobic and electrostatic interactions in the course of the dissolution process of cellulose. The authors outlined that cellulose is an amphiphilic molecule which is able to interact via hydrogen bonding as well as by dispersive forces and electrostatics with the solvent called 'hornification') and result in a decrease in mechanical strength, a lower water retention value and an increased hydrophobicity to mention just the most important ones. These undesired and irreversible changes originate from a change in the supramolecular structure but a detailed knowledge in this area about the structure property relationship is still missing. 2. Results and discussion The insolubility of cellulose in water and many other solvents requires another strategyI for the preparation of thin films. The most convenient way to make amorphous films is the use of trimethylsilyl cellulose (TMSC) which is readily soluble in toluene at a high degree of substitution. ThIn TMSC is spin coated onto a substrate and exposed to HCl vapors for a ceratin time which cleave off the silyl groups ^regeneration) resulting in a smooth cellulose film (d~25 nm) In this contribution, the structural rearrangement of such partly and fully regenerated amorphous cellulose model thin films is investigated by exposing the films to elevated temperature (105 °C) for a prolonged time (6 hours) under ambient atmosphere. This heating procedure is very common in pulp processing and drying of fibers. A structural rearrangement in the films from a featureless to a fibrillar structure is observed upon heating which correlates with the regeneration time and DSSi of the cellulose. (Fig.1) Regeneration Time 0 min 2 min 4 min 6 min 10 min 12 min III Hf m SI B 81 §j Hi .........................................> DS 2.5 DS 2.0 DS0.9 DS 0.1 DS0.1S DS 0.0 Figure 1. AFM height images (1x1 mm ; z-scale, 20 nm) of time-dependent regenerated cellulose surfaces before (upper row) and after (lower row) heat treatment. The DSSi is given for each regeneration time. Results derived from ATR-IR spectroscopy indicate that the hydrogen bonding mode in the films is changed from a mainly O2-H2"O6' (intramolecular) motif to O5"H3-O3' (intramolecular) and O6-H6"O3' (intermolecular) ones upon heat treatment. As proven by grazing incidence X-ray diffraction experiments using synchrotron irradiation, the films retain their amorphous character; probably, small ordered domains are formed which are lacking a long range order. In addition, the heat induced changes enhance BLED, SLOVENIA, 3-5 APRIL, 2013 the order of the supramolecular structure which results in a more pronounced amphiphilic behavior of the cellulose molecules and, a hydrophobization of the surfaces can be observed. While SFEs are in a similar range for non-heat treated and heat treated surfaces, the components of the SFE differ completely. In the case of heat treated films, the dispersive character is the main contribution while in non-heat treated films equal disperse and electron donor components are present. The water sorption capacity is reduced as proven by QCM-D. Upon exposure to water for a prolonged time, the heat treated surfaces do not exhibit changes in morphology while untreated ones are prone to swelling and fine fibrils are formed (Figure 2). A determination of the water content of the nanometric films by QCM-D revealed a decrease from 60 to 31% upon drying. Although there is some evidence for the amphiphilicity of cellulose (e.g. swelling behavior, wettability, SFE), we could not find any proof for hydrophobic interactions in the course of the drying procedure for fully regenerated cellulose films. Probably, these interactions do not play a role in the course of drying at all. In the case of partly regenerated films (RT < 4 minutes), an increase in layer thickness is observed upon heat treatment which indicates a rearrangement due to the minimization of the hyd rophilic/ hydrophobic interactions. However, in these cases the hydrophobic silyl groups can be regarded as the driving force for the rearrangement. These results give new insights into the understanding of the interaction of cellulose with water. Acknowledgements The research leading to these results has received funding from the European Community's Seventh Framework Programme [FP7/2007-2013] under grant agreement no. 214015. We also would like to thank Dr Christian Schuster (Lenzing AG) and Dr Silvo Hribernik for fruitful discussions. Dr Wolfgang Caliebe (DESY - HASYLAB) is acknowledged for experimental support. References For further reading see: [1] Mohan, T.; Spirk, S.; Kargl, R.; Doliska, A.; Vesel, A.; Salzmann, I.; Resel, R.; Ribistch, V.; Stana-Kleinschek, K. Soft Matter 2012, 8, 9807. Session 4: Polymers for Biomedical Applications S4-L10 Poly(ethylene imine) -derived contact biocides: Fabrication of antimicrobially active surfaces Frank Wiesbrock (1,2 ) *, Andrew M. Kelly (1), Verena Kaltenhauser (2 ) and Inge Muhlbacher (1 ) (1) Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, Austria (2) Graz University of Technology, Institute for Chemistry and Technology of Materials, Stremayrgasse 9, 8010 Graz, Austria *frank.wiesbrock@pccl.at Summary. Poly(2-oxazoline)-derived polymers were used as additives in PP compound plates. Antimicrobial activity of these compound plates' surfaces against S. aureus was observed only if partially hydrolyzed poly(2-nonyl-2-oxazoline)s were used as additives, while contact biocidal activity against coli, P. aeruginosa and C. albicans depended only on the degree of hydrolysis of the poly(2-oxazoline)s. 0 1 2 3 4 5 6 1. Introduction The equipment of surfaces with antimicrobially active compounds is aimed for in applications where sterile environments are required despite contact with a large number of individuals [1]. In this context, antimicrobial polymers have gained considerable attention [2]: In addition to the advantage of maintenance-free sterile surfaces, small molecule biocides can be eliminated from this strategy. The mechanism of the permanent antimicrobial activity of polymers has not yet been fully understood: Positive charges in the polymers have been verified as key prerequisite for antimicrobial activity; for the induction of phase separation, hydrophobic alkyl chains in the polymers have been attributed synergistic co-effects [3]. In this study, various poly(2-oxazoline)-derived copolymers were prepared and their antimicrobial activity in compounds was determined in order to contribute to the understanding of the action mechanism of contact biocides. 2. Experimental 2-Ethyl-2-oxazoline E was purchased from Sigma-Aldrich, 2-nonyl-2-oxazoline N was prepared according to a literature recipe [4]. Polypropylene (PP) was provided by Borealis (Linz, Austria). All polymerizations were performed in the microwave reactor Initiator Eight from Biotage. Poly(2-ethyl-2-oxazoline) pE100 and poly(2-nonyl-2-oxazoline) pN100 were prepared according to literature reports from cationic ring-opening polymerizations [5]. Hydrolyses of the polymers at different reaction times provided the AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 copolymers pE10o-25nA25n and pN100.25nA25n (n = 1-4) (Scheme 1); yields: 77-95%. Plate pressing was carried out in a Collin P 200 PV Laboratory Platen Press at 25 bar and 200 °C for 15 min. Biocide tests of the PP (compound) plates were performed at HBICON GmbH at Bielefeld, Germany, in compliance with ISO 22196:2007. r> H> PE100 CP ci" C C CP PA«lO CP CC CP CI" PE7SA25 pE50A50 pE25A76 , H2 Hj Hj H2 ----------------- A> Aj A) A. A» Hi* pN75A25 pN50A50 PN25A75 Scheme 1: Overview of the nine poly(2-oxazoline)-derived polymers investigated for antimicrobial activity. 3. Results and discussion Hydrolysis. Starting from pE100 and pN100, the number of cationic functionalities in the polymers was continuously increased by continued acid-mediated hydrolysis of the amide bonds in an aqueous HCl solution, yielding copolymers of 2-oxazolines E/N and aziridinium chloride A. Optimized work-up conditions enabled the recovery of the (partially) hydrolyzed polymers from extraction procedures in high purity according to 1H-NMR analyses. The degree of hydrolysis was found to follow first-order kinetics for the hydrolysis of both, pE100 and pN100. The hydrolysis rates of pE100 were significantly higher than that of pN100, which seemingly originated from the steric shielding of the reaction center by the nonyl chains that collapsed around the amide bonds in aqueous environments. Specimen Preparation. For the production of PP compound plates, samples of pE100.25nA25n and pN100.25nA25n (n = 0-4) were thoroughly ground and mixed with PP (5/95 w-%). Platen pressing was carried out in a preheated oven. The surface energies of the (compound) PP plates were determined from contact angle measurements and found to be in the range of 25-33 mNm" [SE(PP) = 28.5 mN m" ], indicative of neither pronouncedly hydrophobic nor hydrophilic character. Hence, the wettability of the compound plates was suitable for the application of the compound materials as substitutes for PP-based devices. "Antifouling" properties, nonetheless, cannot be concluded from these data. Antimicrobial Activity. Antimicrobial tests were performed as triplicates in full compliance with ISO 22196:2007 against gram-negative E. coli and P. aeruginosa, gram-positive S. aureus, and the fungus C. albicans. The logarithmic numbers of colony forming units on the plates after 24 h relative to the beginning of the test were used to evaluate the antimicrobial activity. In general, the antimicrobial activity increased with the degree of hydrolysis. Antimicrobial activity against E. coli and C. albicans (Figure 1) was observed starting from hydrolysis degrees of 50% for pE100.25nA25n and pN100.25nA25n (n = 2-4); antimicrobial activity against P. aeruginosa was observed for the same set of polymers with the exception of pE50A50. Against gram-positive S. aureus, however, antimicrobial activity was only observed for polymers that exhibited cationic charges as well as long hydrophobic side-chains, namely pN100.25nA25n (n = 1-3) [6]. The synergism in the interaction of cationic charges and long hydrophobic side-chains was referred to cell perturbation by interactions with membrane components like lipoteichoic acids that are abundant in the outer cell walls of S. aureus. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 Escherichia coli lil lil ±Eh < i ■ o -1 ■ | Pseudomonas aeruginosa | HI Ul 111 < i < i i i < i s - [Staphylococcus aureus | 4 omomomam i < i < <° < ^ < Q. r- 3> n «m is k. Candida albicans 4 iif ^ Q. ? 1000 z 500 0 2000 g 1500 "Si Q. ? 1000 z i- 500 1 1 CM after adsorption X JL 60000 40000 | 2 2500 jJ 2000 ~ 1500 1000 500 0 2500 2000 1500 1000 500 CM after adsorption CM after HUVEC adsorption activation CM CM after HUVEC adsorption activation E g 50000 j 40000 ~ 30000 20000 10000 0 50000 40000 20000 10000 d adsorption activation CM after HUVEC adsorption activation ] CMB 3 CMT b. ^ 30 < ^ 20 10 no adsorbent TNF adsorbent PS-DVB control medium L 4 b no adsorbent TNF adsorbent PS-DVB control medium Figure 2: Effect of mediator modulation with a specific TNF- a adsorbent or a selective cytokine adsorbent endothelial activation. Panel A: release of cytokines; Panel B: expression of adhesion molecules. (PS-DVB) on 5. Conclusions Adsorptive modulation of mediators of inflammation by extracorporeal techniques may be a promising supportive therapy for sepsis, since it reduced endothelial activation in a cell culture model. 6. Acknowledgements This work was funded by the Christian Doppler Society and Fresenius Medical Care (Christian Doppler Laboratory for Innovative Therapy Approaches in Sepsis). Session 11: Advances in Polymer Analysis, Characterisation and Testing S11-L15 Accelerated weathering of multi-layer films - effect of specimen preparation Gernot Oreski (1 )*, Gerald Pinter (2 ) (1) Polymer Competence Center Leoben, RoseggerstraRe 12, 8700 Leoben, Austria (2) University of Leoben, Chair of Materials Science and Testing of Polymers, Otto-GlocklstraRe 2, 8700 Leoben, Austria *oreski@pccl.at 1. Introduction Multi-layer laminates are widely used as backsheet films for photovoltaic (PV) modules. Backsheet materials primarily have to provide mechanical strength and weathering protection to the PV module. Further requirements are low cost, good processability, low water absorption and permeability, high resistance to UV degradation and thermal oxidation, good adhesion to solar cell encapsulation materials and chemical inertness. To fulfill these requirements usually multi-layer films are used. The outer layer serves mainly as a weathering protection. Therefore mainly fluoropolymers such as polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF) or ethylene tetrafluoroethylene (ETFE) are used. But over the last years also new materials like polyethylene terephthalate (PET), polyamide (PA) and even modified polyethylene (PE) were introduced. State of the art for the middle layers are polyesters such as polyethylene terephthalate (PET), mainly to provide mechanical strength as well as electrical insulation and high barrier to water vapor and oxygen. Regarding the inner layer a broad variety of materials can be found on the market, which ranges from a BLED, SLOVENIA, 3-5 APRIL, 2013 symmetrical build-up using the outer layer material, surface modified polyesters to adhesion promoting layers made from polyethylene copolymers. Since PV modules service life times of at least 20 years are requested, it is absolutely essential to analyze the durability of new materials under typical outdoor load conditions and to describe the degradation behavior and its impact on performance of a PV module [1]. Mechanical testing, especially tensile tests, proved to a versatile and sensitive characterization method in describing the aging behavior of backsheet films [2]. During previous research projects after accelerated weathering effects of the multi-layer build-up like delamination were observed that influenced the results of the mechanical testing significantly. Also sample preparation and handling seemed to have an influence on the aging test results [3]. Hence, the main objective of this paper is the systematic investigation of the effect of specimen preparation of laminated multi-layer films on the accelerated weathering test results, especially mechanical testing results. 2. Experimental A three layer laminate consisting of ethylene vinyl acetate (EVA) - PET - fluoropolymer was chosen for the investigations. In order to investigate the aging behavior the specimens were exposed up to 5000h at 85°C and 85 %RH (damp heat test). To investigate the influence of sample preparation, both precut specimen and whole sheets, which have to be cut afterwards, were exposed at damp heat conditions. Furthermore two different specimen geometries (according to ISO 527-3) were investigated: Rectangular strip specimens (type 2) of 100mm in length and 15mm in width and dumb bell specimen (type 5). Tensile tests were carried out with a screw driven universal test machine (Zwick Z010 Allround-Line, Zwick, Ulm, D) at 23°C according to EN ISO 527-3. The test speed was 50mm/min. From a total of at least five specimens for each test series, average numbers for elastic modulus (E), stress-at-break (ab) and strain-at-break (sb) were deduced. 3. Results and discussion Figure 1 shows the cutting edge of specimen that was cut after damp heat exposure. Several cracks with size up to a few millimeters were found after damp heat testing. The crack formation after cutting can be attributed to the strong embrittlement of the PET layer due to hydrolysis. Regarding mechanical testing a significant notch effect of the cracks was found. Therefore it can be concluded that cutting of multi-layer laminate specimen should be done preferably before exposure to accelerated weathering test in order to avoid effects of specimen cutting on the evaluation of the aging behavior. Figure 1. Cutting edge of specimen that was cut after damp heat exposure. Figure 2 shows the stress-strain curves of unaged and aged multi-layer films for both specimen geometries. As expected for the unaged films a significant difference in the deformation behavior and stress-strain curves was found. The mechanical properties exhibited brittle material behavior and are dominated by the PET layer, which is the stiffest material in the laminate. In case of the dumb bell specimen higher stiffness and nearly no plastic deformation was observed. For the strip specimen instead significant plastic deformations with strain-at-break values around 180% were detected. For both films no delamination effects were observed. After exposure to damp heat conditions significantly different mechanical failure was observed for the two specimen geometries. Already after 250h of damp heat testing for the dumb bell specimen a complex fracture behavior with large-scale delamination and consecutive failure of the single layers was observed. For the strip specimen instead until 2000h no delamination effects were detectable. After 5000h the same complex fracture behavior was observed for the strip specimen. Assumedly the dumb bell specimen geometry promotes strong delamination effects after weathering. A possible explanation would be differences in the stress distribution within the specimen, where the different geometries may cause shear or peel stresses. Another reason may be variations in the state of hydrolysis of the adhesive layer due to different moisture ingress for the two geometries. BLED, SLOVENIA, 3-5 APRIL, 2013 strain [%] strain [%] Figure 2. Stress-strain curves of unaged and aged multi-layer films; left: dumb bell specimen; right: strip specimen. The next step within this project will be the clarification of these effects. To assess the influence of humidity specimen of both geometries are currently exposed to dry heat conditions (85°C, humidity not controlled). Furthermore the stress distribution will be modeled via finite element method in order to identify shear or peel stresses. 4. Conclusion and outlook Specimen preparation and handling has a significant influence on the outcome of accelerated weathering tests and the evaluation of aging effects of multi-layer films. The point as well as the mode of cutting had significant influence on the mechanical properties after weathering. Also the choice of the sample geometry is important, as dumb bell specimen geometry supposedly promote stronger delamination effects during mechanical testing than strip specimen. The next step within this project will be the assessment of the influence of humidity and stress distribution on the weathering results of multi-layer films for the different specimen geometries. Acknowledgements Thanks to my colleagues Astrid Rauschenbach, Bettina Hirschmann, Marlene Knausz (PCCL) and Prof. Gerald Pinter (University of Leoben) for the support within this project. This research work was performed at the Polymer Competence Center Leoben (PCCL) within the project "PV Polymer" (FFG Nr. 825379, 3. Call "Neue Energien 2020", Klima- und Energiefonds) in cooperation with the Chair of Materials Science and Testing of Plastics at the University of Leoben. The PCCL is funded by the Austrian Government and the State Governments of Styria and Upper Austria. References [1] A. W. Czanderna, F. J. Pern, Sol Energ Mat Sol C. 1995, 43, 101-181. [2] G. Oreski, G.M. Wallner, R.W. Lang, Biosystems Engineering 2009, 103, 489-496. [3] G. Oreski, Proceedings of SPIE - The International Society for Optical Engineering 7773, 2010, Article number 77730D. S11-L16 Implementation and evaluation of accelerated weathering tests for the aging characterisation of polymer composite films used in photovoltaic modules Bettina Hirschmann*, Gernot Oreski Polymer Competence Center, RoseggerstraGe 12, 8700 Leoben, Austria *bettina.hirschmann@pccl.at 1. Introduction In the photovoltaic (PV) industry it is required to ensure a high quality product standard and as a result module lifetimes of at least 25 years are guaranteed [1]. Therefore not only the module but also the components of a PV module have to be tested concerning the quality. Currently the standard testing method for lifetime valuation of backsheets of PV modules is a damp heat (DH) test at 85°C and 85% relative humidity (RH) for up to 2000 hours (h). The test duration of 2000 h equals approximately 3 months, which takes too long for a fast material pre-selection. Hence the objective of this work was to find an accelerated weathering test to estimate the aging behaviour of polymer backsheet films and to correlate it with the damp heat test for fast qualification of new materials. As accelerated weathering test a pressure cooker test (PCT) was implemented and evaluated. BLED, SLOVENIA, 3-5 APRIL, 2013 2. Experimental A standard composite backsheet film, consisting of polyvinyl fluoride (PVF) and polyethylene terephthalate (PET), was investigated. Samples were artificial weathered under damp heat test conditions up to 3000 h and under pressure cooker test conditions up to 48 h at different temperature levels, which were all above the glass transition of PET (approximately 80°C), shown in Table 1 [2]. The aging behaviour was investigated by differential scanning calorimetry (DSC) and tensile tests according to ISO 527-3 [3]. The DSC tests were performed on the composite film using a Mettler Toledo DSC 1 (Schwerzenbach, CH). Thermograms were recorded under nitrogen environment. The heating rate was 10 K/min. The melting enthalpy of PET which corresponds to the crystallinity degree of the material was evaluated. Tensile tests were carried out by a Zwick-Roell (Ulm, D) Z010 tensile testing machine at 23°C and a crosshead speed of 50 mm/min. Rectangular specimens with a width of 15 mm, a length of 100 mm and a gauge length of 50 mm were used. Table 1. Test conditions Damp heat test Pressure cooker test Temperature 80°C 100°C 110°C 120°C 140°C Relative humidity 85% 100% Duration 500h, lOOOh, 2000h, 3000h 12h, 24h, 48h 12h, 24h, 48h 12h, 24h, 48h 12h, 24h 3. Results and discussion As already shown in the literature, PVF exhibited no significant changes after artificial weathering [4]. This is the reason why only DSC results of PET will be discussed. In Fig. 1 the melting enthalpies of the PET layer are displayed for all unaged and different aged samples. With rising damp heat test duration the melting enthalpy increased from 31.0 J/g ± 0.7 J/g (unaged) up to 44.8 J/g ± 0.8 J/g after 3000 h. The same temperature dependence was found for all specimens after the pressure cooker tests. Pressure cooker tests at 100°C and 110°C for 48 h caused an increase in the melting enthalpy until 12 h of exposure. Then the values after both temperatures stagnated at about 33.6 J/g ± 1.0 J/g and 34.4 J/g ± 2.0 J/g, respectively. Assumedly these temperatures were too low to cause the same amount of physical aging as the damp heat tests within the desired testing time. The samples aged at 120°C for 48 h exhibited a melting enthalpy value of 37.4 J/g ± 1.2 J/g, which correlates with the value of 38.5 J/g ± 1.7 J/g for the damp heat test after 1000 h. By comparison with the damp heat test results also a similar curve progression was found. An aging temperature of 140°C was supposedly too harsh for the material. Already after 24 h strong embrittlement was observed. The melting enthalpy increased from 31.0 J/g ± 0.7 J/g to 47.3 J/g ± 3.6 J/g. Fig. 2 depicts the influence of aging on the strain at break value, which is a sensitive degradation indicator. For all samples an embrittlement after damp heat testing was observed. The strain at break value decreased significantly with increasing test durations. After 2000 h of damp heat testing the samples were brittle and broke before yield stress was reached at a strain at break value of about 1.6% ± 0.2%. After 3000 h of damp heat testing the material was too brittle to cut tensile test samples. High scattering of the results, especially after 1000 h of damp heat testing, was be observed. The material aged under pressure cooker test conditions exhibited similar behavior - with increasing duration the strain at break value decreased. After 48 h at 100°C the strain at break value decreased from 205.3% ± 5.1% (unaged) to 119.7% ± 5.6%. The samples aged at 110°C for 48 h exhibited a strain at break value of 84.0% ± 8.5%. After 100°C and 110°C the curve progressions were different to the damp heat test result within the desired time. Assumedly the exposure at 100°C and 110°C led to a different amount of chemical degradation. By comparison with the other temperatures the results after 120°C correlated the most with the damp heat test results. After 48 h the strain at break value was 41.3% ± 14.6%. In contrary 140°C were supposedly too rough and led to a fast embrittlement with a strain at break value of 0.5% ± 0.2% after 24 h. PCT - Duration (h) 0 52 104 156 545 482 42- c 0> .c «36- 2 30 0 1000 2000 3000 Damp Heat - Duration (h) Figure 1. PET Melting enthalpy of different aged and unaged samples PET Peak 1* Run -1-1- -■— PCT 100°C 100% Nitrogen atmosphere • -PCT 110°C 100% —*— PCT 120°C 100% -»-PCT 140°C 100% V 1A j? -i . ^ Damp Heat 85°C 85%| AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 0 PC?2* Duratlon Kh) 104 -■-PCT 100X100% -•- PCT 110°C 100% -a- PCT 120°C 100% 0 1000 Damp Heat - Duration (h) 2000 Figure 2. Strain at break values over the test duration for unaged and damp heat and pressure cooker aged samples 4. Conclusions and Outlook As an accelerated aging test method pressure cooker tests were implemented and evaluated to estimate the aging behaviour of a standard polymer backsheet films used in PV modules. The aim of this work was to correlate the pressure cooker test (different temperature levels, 100% RH) with the established damp heat test (85°C and 85% RH) for time efficiency. The aging behaviour of the laminate material after damp heat and pressure cooker test aging was characterized by DSC and by mechanical tensile tests. The results of the DSC and the tensile tests exhibited that the pressure cooker test aging at 120°C and 100% RH corresponded the best with the damp heat test. Further investigations of 96 h aged samples under 120°C pressure cooker test conditions will be done for a better verification of the results. In addition infrared spectroscopy analysis of all samples will be conducted to get more information about the degradation behaviour of the polymer laminate under both aging methods. Acknowledgements This research work was performed at the Polymer Competence Center Leoben (PCCL) within the contract project "Implementierung und Evaluierung von beschleunigten Bewitterungstests fur die Alterungscharakterisierung von Polymerfolienverbunden" in cooperation with AT&S AG and with the Institute of Materials Science and Testing of Plastics at the University of Leoben. The PCCL is funded by the Austrian Government and the State Governments of Styria and Upper Austria. References [1] A. W. Czanderna, F. J. Pern, Solar Energy Materials and Solar cells 1996, 43, 101-181 [2] H. Domininghaus, P. Eyerer, P. Elsner, T. Hirth, (7. Ed.); Die Kunststoffe und ihre Eigenschaften, Springer-Verlag, Berlin Heidelberg, 2004, p. 837. [3] ISO 527-3, Plastics - Determination of tensile properties - Part 3: Test conditions for films and sheets [4] G. Oreski, G. Wallner, Solar Energy 2005,79, 612-617 Investigation in the thermal expansion behavior of PV module encapsulation materials Marlene Knausz (1)*, Gernot Oreski (1 ), Peter Guttmann (2) (1) Polymer Competence Center Leoben GmbH, RoseggerstraGe 12, 8700 Leoben, Austria (2) Chair of Materials Science and Testing of Plastics, Montanuniversity, Otto Glockel-StraGe 2, 8700 Leoben, Austria *marlene.knausz@pccl.at Different materials are used in a PV module like glass, polymers, semiconducters and metals. Hence there are different coefficients of thermal expansion (CTE) for these components. These differences can lead to overstressing or even cracking of components. To compensate the different CTEs the solar cells with interconnectors are encapsulated in a low modulus, elastomeric polymer. State of the art for solar cell encapsulation is the usage of ethylene vinyl acetate (EVA). During PV module lamination EVA fits together all components (glazing, interconnectors, cells and backsheet) by melting with following chemical crosslinking. The crosslinking is necessary for the thermo-mechanical stability of the EVA as well as the compensation of the different CTEs of the materials. CTE of EVA is not only important during service life, but also in the lamination process. Inadequate processing and handling of the EVA films can lead to variable CTEs. This can result in troubles during lamination like exorbitant shrinkage, deformation of S11-L17 1. Introduction AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 backsheets, dislocation of cells, breakage of interconnectors and in special cases also to wrinkles in the module[1]. Therefore the main objective was the investigation in the CTE of three commercial available EVA films. 2. Experimental Three different ethylene vinyl acetates (EVA), two standard cure and one ultra-fast cure type were investigated, which are listed in Table 1. Table 1. Investigated EVA films. Abbreviation ENCAPSULANTS Manufacturer Thickness [^m] EVA 1 EVA SC A 400 EVA 2 EVA SC B 460 EVA 3 EVA UFC A 465 Specimen with a length of 10 mm and a width of 6 mm were made out of the above listed materials for CTE measurements. At least three measurements of each direction (along and across extrusion direction) per film were made. The measurements were carried out using a thermomechanical analyser (TMA) of the type Mettler Toledo TMA/SDTA840 (Schwerzenbach, CH). The measurements were all done in air atmosphere and started at 25 °C for 3 min then the sample was heated up with a heating rate of 2 K/min until 70 °C were reached for encapsulants. All tests were done in air atmosphere. The CTE was evaluated then by _ i i2 ath — , x t !0 ' 2 (1) l0 is the initial length of sample, before measurements are started; l2 is the length at end temperature (T2=60 °C) and lj is the length at starting temperature (Tj=30 °C) of evaluation. 4. Results and discussion Figure 1 shows CTE as a function of temperature in machine and transversal direction for all investigated films. The first change of the slope of CTE values at 40 °C can be related to the melting of secondary crystals in EVA due to storage at slightly elevated temperatures. The melting temperature of EVA can be found around 60 °C. Above 60 °C the material softens and no reliable results were obtainable. With increasing temperature all films showed an increase in CTE values. Furthermore, an anisotropic behaviour of the CTE was found for all films. In transversal direction the CTE was higher than in machine direction. These can be attributed to the orientations of the chain molecules out of the extrusion process. Interestingly the films of manufacturer A exhibited a far more significant anisotropy, which can be related to higher orientation. This clearly indicates that the production parameters like drawing off speed of the film from manufacturer A was too fast. Also the CTE values of the films of manufacturer A were higher than the values of manufacturer B. EVA 1 has an over 3,5 times and EVA 3 has an over 6 times higher value of the CTE in machine direction at 60 °C than EVA 2 from the manufacturer B. To confirm these assumptions and to identify all reversible effects from film production rerun measurements (3 reruns with the same specimen) with an EVA 1 sample in machine and transversal direction was made. Due to the melting of the films all orientations relaxated and resulted in significant lower CTE values similar to EVA 2. Also the differences between machine and transversal direction were minimized. This confirms the assumption of former induced orientation effects due to extrusion. O E a. a. EVA 1.................................... -machine direction -transversal direction .............J] Era 1441 LfflDg fflassse O E 10000 - 4000- EVA 2............................................................ -machine direction j -transversal i 40 45 50 Temperature [°C] 40 45 50 Temperature [°C] b) 10000 8000 3000 6000 5000- 4000 2000 2000- 0 30 35 55 5C 30 35 55 50 AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 E a. a. 10000 6000 2000 EVA 3..............1....................... -machine direction -transversal direction 30 35 55 60 40 45 50 Temperature [°C] c) Figure 1. CTE as a function of temperature in machine and transversal direction for a ) EVA 1 b ) EVA 2 c ) EVA 3 8000 4000 0 5. Conclusions The results showed a temperature dependency on the CTE of the investigated EVA samples. Furthermore, an anisotropic behaviour of the CTE was found for all films. The differences in machine and transversal direction can be attributed to orientations of the chain molecules due to the extrusion process. Strong anisotropy can result in troubles during lamination like exorbitant shrinkage, deformation of backsheets, dislocation of cells, breakage of interconnectors and in special cases also to wrinkles in the module. TMA proved to be a suitable method for qualification but also for quality control of different encapsulation films. Acknowledgements The research work was performed at the Polymer Competence Center Leoben GmbH (PCCL, Austria) in cooperation with the Institute of Materials Science and Testing of Plastics at the University of Leoben within the framework of the COMET-program of the Austrian Ministry of Traffic, Innovation and the Ministry of Economy, Family and Youth with contributions by academic and commercial partners. The PCCL is funded by the Austrian Government and the State Governments of Styria and Upper Austria. References [1] C. Hirschl et al. (2012). In Proc. "EU PVSEC 2012", (Nowak, S. und Jager-Waldau, A.), 4BV.3.55, Frankfurt, D. S11-L18 Characterisation of the damping behavior of thin multilayer films Gilbert Knapp (1)*, Gernot Oreski (1 ), Gerald Pinter (2 ) (1) Polymer Competence Center Leoben, Roseggerstrasse 12, 8700 Leoben, Austria (2) University of Leoben, Material Science and Testing of Plastics, Otto Glockel-Strasse 2, 8700 Leoben, Austria *gilbert.knapp@pccl.at 1. Introduction In structures, which are exposed to high frequencies the knowledge of the damping behavior is essential for a successful design. In the present work a method is introduced to study the temperature and frequency dependent damping behavior of thin multilayer polymer films with an overall thickness below 50 |im, based on the concept of dynamic mechanic analysis (DMA). 2. Theory The damping of the investigated thin multilayer films happens due to the constraint layer effect, i. e. damping occurs due to shear deformation of a soft viscoelastic layer constrained by two stiff outer layers when the sandwich design is bent, as depicted in Figure 1 [1-5]. Therefore to characterize the damping behavior of thin multilayer films without the need to build up the whole structure a test was set-up in DMA-shear mode. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED. SLOVENIA. 3-5 APRIL. 2013 Constraining layers application experiment Figure 1. Schematic diagram of the constraint layer concept where damping in a sandwich design occurs due to shear deformation of a soft viscoelastic layer which is constraint by two stiff layers and comparison of the load situation in application and in the experiment [1-5]. 3. Experimental A dynamic mechanic analyzer (DMA) of the type Mettler Toledo DMA/SDTA 861e with special shear clamps was used to characterize thin multilayer films with thicknesses below 50 |im due to their damping behavior in a temperature range from -40 up to 220 °C and frequencies from 1 to 200 Hz. During a dynamic heating segment of 2 K/min frequencies of 1, 10, 100 and 200 Hz were altered continuously. To prevent the shear brackets from contact quartz plates where attached between the specimens and the brackets. Subsequently the frequency-temperature behavior of the loss factor tan d maximum was described via the Williams-Landel-Ferry concept (WLF) and the temperature for the tan d maximum at application relevant frequencies up to 800 Hz was calculated [6]. This frequency was chosen because in the application the laminates have to damp the whole structure, which they are built in, at the resonance frequency at 800 Hz. In order to obtain an easy to use factor which should be comparable with experiments of the whole structure the frequency dependent integrated average of tan d was calculated in a temperature range relevant for the application from Oto 60 °C. 4. Results and discussion In Figure 2 results from DMA experiments with frequencies of 1, 10, 100 and 200 Hz and the succeeding calculation of the integrated average of the loss factor tan d are shown. The tan d curves exhibited a sharp increase starting at -40 °C, followed by a broad maximum, a plateau with a lower damping levels and a decrease starting at 140 °C. Whereas the maximum was related to the softening of the viscoelastic adhesive layer, the decrease starting at 140 °C was related to the glass transition of the stiff outer layers. With increasing frequencies a broadening and a shift to higher temperatures of the loss factor maximum was found. The latter was described via the WLF concept followed by a calculation of tan d curves for frequencies up to 800 Hz by shifting the whole curve from 200 Hz, as depicted in Figure 2(a). The maximum of the loss factor shifted over 23 °C from -18 °C at 1 Hz to 5 °C at 200 Hz and an additional difference of 9 °C was calculated for the maximum at 800 Hz and 14 °C. Finally the integrated average of tan d in the temperature range from 0 to 60 °C, which is relevant for the application, was calculated for frequencies from 1 to 800 Hz. Also for the integrated average of the loss factor tan d frequency dependent damping behavior was found with significant lower loss factors at frequencies below 100 Hz. cl0°L • 10 Hz • 200 Hz U 1.0 B ... ___ 0.9 co h— JS II/ -™ r Tai \ . 70- 60- e ul 50- * 411- m f> 30- o — ?n- I m 10- a 0- Owl-* 0.2wt -% 0.5WI-* 1 Owl-* 2 Owl-* Exposure [J/crrr Figure 2. Relative film thickness versus irradiation dose of photochemically foamed ink formulations containing different levels of a) photoacid generator and b) photosensitizer concentration In particular, the most intensive expansion of the film thickness is observed with 0.5 wt.-% photosensitizer, leading to an almost a doubling of the thickness of the ink layer. The corresponding cell morphology is shown in Figure 3c and reveals that dense cells are achieved with diameters ranging from 5 to 14 |im. With respect to foamed inks containing only the photoacid generator, lower cell densities and the cell diameters (1 - 7 |im) are observed (see Figure 3b). Both the results of the cell morphology and the film expansion give a good indication that a higher amount of blowing gas can be released compared to the foaming without any photosensitizer. Figure 3. Optical micrographs of foamed ink layers a) prior to and b,c) after UV illumination 4. Conclusions Due to the photochemical foaming employing a photoacid generator and calcium carbonate particles, 3D structures can be produced in offset printing techniques with one process step. The foaming proceeds at room temperature and can be accomplished within seconds. Additionally, it makes the formation of firm and raised structures feasible by applying only one ink layer. Acknowledgements This study was performed at the Polymer Competence Center Leoben GmbH (PCCL, Austria) within the framework of the COMET-program of the Federal Ministry for Transport, Innovation and Technology and the Federal Ministry for Economy, Family and Youth with contributions by the University of Leoben, Graz University of Technology and Joanneum Research Forschungsgesellschaft mbH. References [1] S. Schlogl, M. Reischl, V. Ribitsch, W. Kern, Prog. Organ. Coat. 2012, 73, 54-61. [2] Y. Yagci, I. Reetz, Prog. Polym. Sci. 1998, 23, 1485-1538. BLED, SLOVENIA, 3-5 APRIL, 2013 S7-L20 Organic-inorganic hybrid silver nanocomposites as antimicrobial corrosion protective coating materials Deewan Akram (1,2 )*, Eram Sharmina (1 ) , Sharif Ahmada (1) (1) Materials Research Lab., Dept. of Chemistry, Jamia Millia Islamia, New Delhi-110025, India (2) Dept. of Chemistry, Faculty of Science, Jazan University, Jazan, P.O. Box 2097, Saudi Arabia *deewanakram@gmail.com Abstract Organic-inorganic hybrid materials have been prepared with the goal of combining properties of inorganic and organic materials. These hybrid materials provide synergistic properties of organic matrix such as environment friendliness, lightweight, flexibility, good impact resistance and good process ability, and inorganic components which improve physical, good chemical resistance, mechanical, and thermal properties, as well as gas barrier and photonic properties. In this work, attempt has been made for hydroxylation of linseed oil through non-isolable epoxide intermediate forming polyol [Lpol]. Lpol was treated with TEOS resulting in organic-inorganic hybrids (LPOSi), preparation of silver nano-particles in organic-inorganic hybrids (LPOSi) via reduction of silver salt (AgNO3) by employing W,W-dimethylformamide (DMF) as reducing agent at room temperature to obtain organic-inorganic hybrid silver nanocomposites (Ag/LPOSi), the latter underwent polyaddition reaction with toluene-2, 4-diisocyanate [TDI] to form their polyurethane (Ag/LPOSiPU). UV-visible and TEM studies substantiate the formation of silver nanoribbons of average length < 500nm, width 10nm and thickness around 4nm, along with silica nanoparticles of diameter 50-80 nm. Thermogravimetric analysis showed improved thermal stability of Ag/LPOSiPU. The physicomechanical and corrosion resistance performances (in various corrosive media) tests of Ag/LPOSiPU coatings were also conducted to evaluate their coating properties. These studies revealed that the incorporation of silver nanoparticles has a significant influence on structural and physico-chemical aspects. The polymer nanocomposites exhibit enhanced antimicrobial efficacy against S. aureus and E. coli, respectively, and will pave way in plethora of biological and chemical applications as coating materials. References [1] D.Akram, S.Ahmad, E.Sharmin, S.Ahmad, Macromol.Chem.Phys. 2010, 211, 412-419. [2] A.Kumar, P.K.Vemula, P.M.Ajayan, G.John, Nature Materials, 2008, 7, 236-241. S7-L21 Water-developable Poly(2-oxazoline ) -based photoresists Martin Fimberger (1,2)*, Verena Schenk (1,2 ) , Elisabeth Rossegger (1,2) and Frank Wiesbrock (1,2 (1) Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, Austria. (2) Graz University of Technology, Institute for Chemistry and Technology of Materials, Stremayrgasse 9, 8010 Graz, Austria. *martin.fimberger@pccl.at Summary. Two copolymers, namely pEtOx80Bu~Ox20 (composed of 2-ethyl- and butenyl-2-oxazoline) and pPhOx80Dc~Ox20 (composed of 2-phenyl- and 2-9'-decenyl-2-oxazoline), were synthesized in a microwave reactor in less than 100 minutes. Copoly(2-oxazoline)-based photoresist formulations containing the copolymer, a tetrathiol and a photoinitiator were prepared in 1-methoxy-2-propanol. Films of the copolymers were crosslinked via thiol-ene reactions upon irradiation, reproducing patterns preset by the masks. The photoresist pEtOx80BuOx20 could be developed in water, revealing resolutions of 2 |im. 1. Introduction Photolitography resembles the state-of-the-art technology for manufacturing printed circuit boards and integrated circuits. Thin three-dimensional structures can be patterned to various surfaces [1] either as positive or negative reproduction, depending on the kind of photoresist used. The current work aimed at the preparation of a high-resolution negative photoresist with tailor-made adhesion. 2-Oxazolines comprise a vast number of easily obtainable differently substituted congeners which allows for the synthesis of (co-)polymers with various different characteristics [2-4]. The living cationic ring-opening polymerization of 2-oxazolines is usually supported by microwave radiation which grants narrow molecular weight distributions and reasonably short reaction times [5,6]. For the application of the poly(2-oxazolines) as negative photoresists, olefinic side-chains were chosen as reactive sites for the tetrathiol during crosslinking. 2-3'- UV AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 2. Experimental With the exception of commercially available EtOx, all other monomers were synthesized according to literature procedures: PhOx was obtained by the procedure of Witte and Seeliger, and Dc=Ox according to the method described in a Henkel Patent [2,3]. Bu=Ox was prepared via a three-step synthesis [4]. The copolymerizations (Scheme 1) were conducted in a microwave reactor under autoclave conditions, which allowed for reaction times of 100 minutes or less and sufficiently low molecular weight distributions (PDI < 2) [7]. For the formulation of the photoresists, 25 wt.-% of the copolymer were dissolved in 1-methoxy-2-propanol. The amount of crosslinker 4SH (Scheme 1) was calculated for quantitative conversion of the olefinic side-chains (ratio SH:ene = 1:1). As photoinitiator, PI (Scheme 2), Lucirin TPO-L™ was added. The resists were cast onto the substrates and UV-illuminated through a quartz mask. Scheme 1: Reaction scheme of the cationic ring-opening polymerization of 2-oxazolines (left) and structures of the copoly(2-oxazoline)s pEtOx80Bu"Ox20 and pPhOx80Dc"Ox20 as well as the thiol crosslinker 4SH (right). 3. Results and discussion Two different copoly(2-oxazoline)s, one hydrophilic and one hydrophobic representative, were evaluated. The copolymers contained 20 mol-% of the monomer bearing the olefinic motif (Bu~Ox, Dc~Ox) and 80 mol-% of the monomers with the non-functionalized side-chains (EtOx, PhOx), providing quantitative crosslinking upon UV irradiation (see below). Keeping future scale-up in mind, commercially or synthetically easily available monomers were used whenever possible: Bu~Ox was chosen as hydrophilic monomer and Dc~Ox, which can be easily prepared from 10'-undecenoic acid from renewable resources, as hydrophobic monomer. Copolymerizations were conducted in a microwave reactor under autoclave conditions. XH-NMR analyses confirmed polymerization degrees of 100 and monomer compositions of 80:20 as targeted. 25 wt.-% solutions of the polymers in halogen-free 1-methoxy-2-propanol were prepared, and the crosslinker 4SH and photoinitiator PI were added. The formulations could be stored for three months at ambient temperature without the need of additional stabilizers. The crosslinking photoreaction was initiated by illumination with UV-light, which homolytically cleaved the photoinitiator and yielded two radicals that started the thiol-ene reactions (Scheme 2). The illuminated resists could be developed either in 1-methoxy-2-propanol or, in the case of pEtOx80Bu"Ox20, in water. In order to characterize the achievable resolution, pEtOx80Bu"Ox20 was spincoated onto CaF2 substrates, illuminated through a mask aligner system and developed. The photoresist pattern was visualized by an optical microscope and exhibited resolutions of 2 |im. Storage of the photoresist formulations for several months had no adverse effect to the attainable resolution. Scheme 2. Photoinitiator decomposition and initiation of the thiol-ene click reaction (left) and thiol-thiyl cycle during the thiol-ene reaction (right). The structure of the photoinitiator PI is shown in the left half of this scheme. Copoly(2-oxazolines) with olefinic side-chains can be crosslinked in the film-state employing thiol-ene click reactions with a tetrathiol. Formulations of the copoly(2-oxazoline)s, a tetrathiol, and a photoinitiator revealed stability for several months. Photoresists that were cast onto substrates enabled 2.5-dimensional patterning after UV illumination and subsequent development: Geometric pattern preset by masks were reproduced with resolutions in the 2 mm range. Acknowledgements This study was performed at the Institute for Chemistry and Technology of Materials of the Graz University of Technology and the Polymer Competence Center Leoben GmbH (PCCL) within the framework of the Kplus-program of the Austrian Ministry of Traffic, Innovation and Technology. PCCL is funded by the Austrian Government and the State Governments of Styria and Upper Austria. ry R* + HS—R R'H+ RS • 4. Conclusions BLED, SLOVENIA, 3-5 APRIL, 2013 References [1] E. Reichmanis, O. Nalamasu, F.M. Houlihan, Acc. Chem. Res. 1999, 32, 659-667. [2] H. Witte, W. Seeliger, Liebigs Ann. Chem. 1974 ,996-1009. [3] M. Beck, P. Birnbrich, U. Eicken, H. Fischer, W.E. Fristad, B. Hase, H.-J. Krause, Angew. Makromol. Chem. 1994, 223, 217-233. [4] A. Gress, A. Volkel, H. Schlaad, Macromolecules 2007, 40, 7928-7933. [5] F. Wiesbrock ,R. Hoogenboom, M.A.M. Leenen, S.F.G.M. van Nispen, M. van der Loop, C.H. Abeln, A.M. van den Berg, U.S. Schubert, Macromolecules 2005, 38, 7957-7966. [6] R. Hoogenboom, F. Wiesbrock, H. Huang, M.A.M. Leenen, H.M.L. Thijs, S.F.G.M. van Nispen, M. van der Loop, C.-A. Fustin, A.M. Jonas, J.-F. Gohy, U.S. Schubert, Macromolecules 2006, 39, 4719-4725. [7] V. Schenk, L. Ellmaier, E. Rossegger, M. Edler, T. Griesser, G. Weidinger, F. Wiesbrock, Macromol. Rapid Commun. 2012, 33, 396-400. S7-L22 Monitoring the copolymerization of vinyl acetate and ethylene in emulsion using a high pressure RC1 reactor: a case study Ida Poljanšek (1 ), Klemen Burja (1 )*, Ema Fabjan (1 ) , Dolores Kukanja (1,2) (1) Centre of Excellence PoliMaT, Tehnološki park 24, 1000 Ljubljana, Slovenia (2) Mitol, Partizanska cesta 78, 6210 Sežana, Slovenia *klemen.burja@polimat.si 1. Introduction The free radical polymerization of vinyl acetate in emulsion is commercially conducted either in batch or continuous reactor at atmosphere pressure. In order to improve the properties of poly(vinyl acetate) (PVA) a co-monomer can be added and copolymerized with the vinyl acetate [1]. In this work we present the high pressure synthesis of vinyl acetate and ethylene (VAE) copolymers in emulsion with different contents of ethylene monomer [2]. The polymerization of vinyl acetate (VAc) and ethylene (E) was carried out in a Mettler Toledo RC1 high pressure batch reactor enabling an accurate control of reaction parameters as well as in-situ monitoring of the copolymerization reaction and the consumption of monomers. 2. Experimental The emulsion synthesis of VAE copolymers with different contents of ethylene was carried out in RC1e - reaction calorimeter equipment (Mettler Toledo) in a 1.8 L HP60 high pressure stainless steel semi-batch reaction vessel, a stainless steel-anchor stirrer, a digital thermometer, a calorimeter probe and FTIR K6 conduit 16 mm Dicomp probe. Ethylene consumption during the polymerization process was measured by gas uptake unit while pressure in the vessel was controlled by external automatic gas valve. HP60 Prominent Micro delta Optodrive pump was used for dosing of vinyl acetate. The temperature, dosing and pressure during the polymerization were accurately controlled by Mettler Toledo iControle software. Vinyl acetate was introduced into a water solution of the polymer surfactant poly(vinyl alcohol) (mixture of two polyols with different molecular weight in concentration 3.5 wt.%, Mw=160.000, and 7 wt.%, Mw=31.000), 0.1 wt.% ammonium persulfate as initiator and ethylene in a controlled manner (dosing time from 180 to 240 min). The applied pressure of ethylene during the polymerization at 75 °C was controlled by automatic pressure valve either at 20 bar or 30 bar. The reaction was monitored by in-situ Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR). Particle size growth and particle size distribution was determined by in-situ Focused Beam Reflectance Measurement (FBRM) while the ethylene consumption was measured by a pressure drop in a gas tank. During the VAc dosing process at 75 °C polymerization heat release was measured to monitor the course of the reaction and ethylene incorporation in the VAE dispersions. The resulting copolymer composition and thermal properties were determined by 1H NMR spectroscopy and Differential Scanning Calorimetry (DSC). 3. Results and discussion The course of copolymerization between vinyl acetate and ethylene at 75 °C was studied in-situ by ATR-FTIR transmission probe immersed directly into the pressure reactor. The concentration profiles for VAc, E and VAE copolymer at 75 °C are presented in Figure 1. The relative ratios of the monomeric units in the copolymer were determined by comparing the intensities (areas) of the characteristic bands of VAc (C-O and C=O stretching at 1138 cm"1 and 1738 cm"1, respectively) and ethylene (C-H stretching at 2864 cm"1). After the total addition of VAc its amount in the reaction mixture decreases rapidly during the copolymerization. Moreover, the slower dosage of VAc into the reaction mixture leads to an increase in ethylene units in the copolymer as determined by NMR and gas consumption analysis. Weight percent of incorporated ethylene was calculated using Flory-Fox theory by Tg determination of VAE with DSC method. Particle size growth was monitored by in-situ FBRM method. Since the method does not differ among different particle forms, particle counts represent a sum of emulsified vinyl acetate monomer droplets and emerging dispersed copolymer particles. Particle BLED, SLOVENIA, 3-5 APRIL, 2013 size distribution curves for particles under 50 |im showed similar trends as indicated by ATR-FTIR curves for formation of VAE dispersion. After copolymer dispersion was formed (when approx. one third VAc was added), median of measured particle size remained constant with about 3.8 |im and matched the average particle size of 3.4 |im for end VAE dispersion as measured by dynamic light scattering. Ethylene pressure in the reaction vessel was kept constant during the whole polymerization process by automatic gas valve. Ethylene consumption was measured and calculated by pressure drop in gas dosing tank. The ethylene monomer unit content in VAE copolymer was determined by 1H NMR and calculated from Tg obtained from DSC analysis. The obtained results matched the measured ethylene molar consumption. Figure 2 shows total heat of polymerization at 75°C, 30 bar of ethylene and 240 min of VAc dosing. During polymerization 324.7 kJ of heat was released and represents sum of released polymerisation heat for 2.9 mol VAc (258.8 kJ) and 65.9 kJ of released heat for ethylene, which is 0.7 mol of ethylene (polymerisation heat for VAc is 89.12 kJ/mol [3] and ethylene 94.5 Figure 1. The concentration profiles in weight % for vinyl acetate, ethylene, and reaction product VAE during the copolymer | synthesis at 75°C based on in situ ATR-FTIR measurements Figure 2. The heat release during the polymerization performed at 75 °C (gray area). The corresponding conversion and particles count curves are marked in gray and black, respectively. flSPM 2013 ** AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 3. Conclusions RC1 reactor calorimeter was used for the preparation of VAE copolymers as it enables the accurate setting and control of the reaction conditions (temperature, pressure and monomer dosing). In situ ATR-FTIR spectroscopy, FBRM, gas consumption and calorimetric measurements were used for monitoring the course of reaction, while DSC evaluation and 1H NMR spectroscopy of the resulting copolymer were applied for the determination of the ethylene monomer unit contents. Acknowledgements The authors wish to gratefully acknowledge Mitol, Sežana for providing all chemicals used in this study and for permission to publish this paper. This work was supported by the Ministry of Education, Science, Culture and Sport of the Republic of Slovenia Grant number 3211-10-000057 (Centre of Excellence for Polymer Materials and Technologies). References [1] K. Geddes, Handbook of Adhesive Technology, Marcel Dekker, New York, 1994, Chapter 35. [2] I. Poljanšek, E. Fabjan, K. Burja, D. Kukanja, accepted for publication in Progress in Organic Coatings [3] www.vinylacetate.org/properties.pdf [4] http://www.journaloftheoretics.com/Articles/2-1/ZP-fp.htm Session 8: Theory, Modeling and Simulations S8-L23 Dendritic vs linear polymer brushes in planar and spherical geometries Tatiana M. Birshtein (1)*, Alexey A. Polotsky (1), Oleg V. Borisov (1,2 ), Oleg V. Rud (1) (1) Institute of Macromolecular Compounds, Russian Academy of Sciences, 31 Bolshoy pr., 199004 St.-Petersburg, Russia (2) Institut Pluridisciplinaire de Recherche sur l'Environnement et les Materiaux, UMR 5254 CNRS/UPPA, Pau, France *birshtein@imc.macro.ru 1. Introduction The polymer brush is among the best studied systems in polymer science. Brushes, formed by long polymer chains densely grafted to a solid-liquid or to a liquid-liquid interfaces, received ample attention from both theoretical and experimental perspectives. In the meantime, advanced synthetic approaches now allow the making of macromolecules with a virtually arbitrary complex and well-controlled branched architecture (stars, combs, dendrons). Moreover, the technology to attach these to surfaces becomes available. It is believed that brushes from branched architectures may introduce novel desired features, such as enhanced stimuli responsiveness, outstanding nanomechanical properties, and tuned biointeractivity. From a physical point of view, brushes of branched macromolecules are challenging because the distribution of the elastic tension and the fluctuations of the individual molecules is far from trivial as these properties will differ from the behavior of the same molecules in solution. In the present work, equilibrium structural properties of planar and spherical polymer brushes formed by dendritic polymer chains (dendrons) are studied by means of Scheutjens-Fleer self-consistent field (SF-SCF) modeling and scaling analysis. 2. Model We consider a spherical polymer brush formed by dendrons grafted by the terminal (root) segment onto the surface of a spherical core particle of radius R0 at the density a (number of dendrons per unit area) and immersed in a good (athermal) solvent. A dendron is characterized by the number of generations g, and a functionality q of each branching point. The functionality is defined as the ratio between the number of spacers in generation g+1 and that in generation g. The number of monomer units per spacer, n, is fixed throughout the dendron. We assume that the spacers in the dendrons are intrinsically flexible. 3. Results and discussion We demonstrate, that the effect of the branched topology of individual macromolecules forming the brush on the integral structural properties of the brush can be accounted for by using the universal scaling parameter N/M > 1, where N is the total number of monomer units in a dendron and M is the number of monomer units in the longest elastic path. In the limit M = N = 1 the properties of the brushes formed by end-grafted linear polymers are recovered. As follows from the results of SF-SCF modeling, in both linear and dendritic spherical brushes a variation of the ratio of the surface curvature radius R0 to the characteristic brush thickness H affects not only the shape of the monomer density profile, but also the character of fluctuations in extension of individual macromolecules forming the brush: In linear brush the density decreases as a power-law function of a distance from the center and chain ends distribution is peaked near the edge of the brush at small R0 , whereas at large R0the density decay is weaker and the chain ends are distributed throughout the brush. In contrast, in dendritic brush the density distribution is fairly uniform irrespectively of the ratio R0/H. This uniform density distributions are assured by fairly uniform distribution of the end segments throughout the brush at R0/H << 1 or by multi-modal distribution of the overall extension of dendrons at R0/H >> 1. The latter means that an increase in the curvature radius of the surface is accompanied by BLED, SLOVENIA, 3-5 APRIL, 2013 emerging segregation into two (or more, for larger number of generations) populations of dendrons: the less extended and the more extended ones. The former ones fill the space in the central region of the brush, the latter brings the majority of the monomer units closer to its periphery. Acknowledgements This work has been partially supported within Scientific and Technological Cooperation Program Switzerland-Russia, project " Experimental studies and theoretical modelling of amphiphilic di-/triblock and dendritic functional polymers at surfaces: influence of interfacial architecture on biological response", Grant Agreements No. 128308, by the Russian Foundation for Basic Research (grants No. 11-03-00969a and No. 12-03-31243) and by Department of Chemistry and Material Science of the Russian Academy of Sciences. References [1] A.A. Polotsky, T. Gillich, O.V. Borisov, F.A.M. Leermakers, M. Textor, T.M. Birshtein, Macromolecules 2010, 43, 9555-9566. [2] A.A. Polotsky, F.A.M. Leermakers, E.B. Zhulina, T.M. Birshtein, Macromolecules 2012, 45, 7260-7273. [3] O.V. Rud, A.A. Polotsky, T. Gillich, O.V. Borisov, F.A.M. Leermakers, M. Textor, T.M. Birshtein, submitted to Macromolecules 2012. S8-L24 Collective ordering of colloids in grafted polymer layers Tine Curk (1) , Francisco J. Martinez-Veracoechea (1) , Daan Frenkel (1), and Jure Dobnikar (1, 2 ) * (1) Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW, Cambridge, UK (2) Department for theoretical physics, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia *jd489@cam.ac.uk A grafted polymer layer can be used to prevent large colloidal particles from reaching a solid surface. However, under the influence of a sufficiently strong external field, the colloids will penetrate and form solid-like structures within the polymer layer. The polymer-mediated colloidal interactions are typically of the order of kBT (i.e., comparable to the entropic terms). The colloid-polymer mixtures are thus inherently less ordered than molecular systems. Sufficiently strong external forces constrain the translational degrees of freedom of the colloids, and enable the weak polymer-induced interactions to steer the assembly into ordered patterns. We present Monte Carlo simulations of colloidal particles pulled into grafted polymer layers by constant external force. The insertion free energy of a single colloid into the polymer layer is qualitatively different for surfaces with an ordered and a disordered distribution of grafting points. Moreover, the tendency of colloidal particles to traverse the grafting layer is strongly size dependent. In dense colloidal suspensions, under the influence of sufficiently strong external force, a collective instability allows the colloids to penetrate and form internally ordered, columnar structures spanning the polymer layer. Depending on the conditions, these colloidal clusters may be isolated or laterally percolating. The morphology of the observed patterns can be controlled by the external fields, which opens up new routes for the design of thin structured films. Figure 1. Cluster growth sequence and phase diagram of lateral colloidal structures in grafted polymer layers.. References [1] T. Curk, F.J. Martinez-Veracoechea, D. Frenkel, and J. Dobnikar, submited (2012) O^t^o A S P M 2013 RUSTRIRN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA 3-5 APRIL, 2013 S8-L25 Effect of polymer-colloid interactions on polymer-mediated forces and selected static and dynamic properties of polymer-nanocolloid sytems Alexander I. Chervanyov*, Gert Heinrich Leibniz Institute of Polymer Research Dresden, Hohe 6, 01069, Dresden, Germany *chervanyov@ipfdd.de 1. Effective interaction between colloids mediated by non-adsorbing and reversibly adsorbing polymers In order to study the effect of the polymer adsorption on the polymer-mediated (PM) interactions between nano-colloids, we have performed a comparative analysis of these interactions mediated by non-adsorbing and reversibly adsorbing excluded volume polymers by developing and making use of an analytic theory [1,2]. As a first application of this theory, we have calculated the potential of the depletion interactions acting between nano-colloids immersed in the bath of non-adsorbing polymers as a function of the separation H between colloids. Figure 1 shows the comparison of our theoretical findings with the results of Monte Carlo simulations of the depletion potential U in the protein limit where the colloid radius R is much smaller than the polymer gyration radius RG. As is clearly seen from this Figure, the developed theory adequately describes the Monte Carlo simulation results [3] in the domain of polymer concentrations spanning across the dilute to dense regimes. O.O-i -0.1-0.2-0.3-0.4-0.5- ? . * S -A / £ » ' / > 0.0 0.1 ■ 1=0.43, MC simulations • i=1.29, MC simulations i i=2.58, MC simulations ♦ i=5.16, MC simulations - 4i=0.43, theory -- 41=1.29, theory 4>=2.58, theory — 4i=5.16, theory 0.2 0.3 (H-2R)/RG 0.4 0.5 Figure 1. Comparison between theoretical results and Monte Carlo simulations [3] of the PM potential for several values of the polymer volume fraction 9 and the colloid radius R=0.1RG. As a next step, we have calculated the potential of the polymer mediated interactions for the case of reversibly adsorbing polymers as a function of colloid radius R, separation H, polymer correlation length {;, polymer volume fraction 9 and the introduced absorbance a that quantifies the affinity of the colloid surface for polymers. The developed theory describes the limit of the weak adsorption where the correlation length ^ of the excluded volume polymer system is much smaller than the characteristic adsorption length (colloid absorbance) a. Similarly to the case of non-adsorbing polymers, the resulting expression for the PM potential U mediated by adsorbing polymers is shown to factorize into the product of the immersion free energies of the colloids and the correlation function of the uniform polymer system. A typical example of the calculation of U for several values of the reduced colloid radius R/J; and ^/a=0.1 is shown in Figure 2. Note that according to Figure 2, the dependence of the magnitude of the PM potential U on the colloid radius R for the case of adsorbing polymers shows just the opposite trend in comparison with the purely entropic depletion potential that increases with R. This difference stems from different dependencies of the colloids immersion energy W on its radius R for the above cases of non-adsorbing and adsorbing polymers. Specifically, in the case of non-adsorbing polymers W occurs to be proportional to the colloid surface ~R2. The dependence W(R) for the case of adsorbing polymers is much less pronounced, for that the main factor affecting the immersion energy in this case is the strength of the adsorption interactions. The above explained qualitative difference between the dependencies W(R) for adsorbing and non-adsorbing polymers results in the above mentioned quantitative difference in the dependencies U(R) for the above two cases that can be elucidated from Figures 1 and 2. 2. Equation of state of the colloid-polymer-solvent system in the presence of adsorption interactions between polymers and colloids By making use of the obtained results for the potential of PM interactions mediated by adsorbing and non-adsorbing polymers, we have calculated the equation of state (EOS) of the nanocolloid-polymer-solvent system for the respective cases of polymer adsorption. For the case of non-adsorbing polymers, the equations of state shows non-trivial dependence on the polymer volume fraction that is overlooked by the previous theories. For the case of reversibly adsorbed polymers, the obtained EOS exhibits a complicated interplay between the purely entropic forces and the adsorption interactions that leads to different phase behavior of the colloid-polymer system in dependence on the colloid radius, affinity of the colloid surfaces for polymers, and the volume fractions of colloids and polymers in solution. As a main result of the described studies, we have identified the relative significance AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA 3-5 RPRIL, 2013 of the entropic interactions, physical adsorption and bridging of colloids by polymers for different domains of the above listed parameters. On -1 - / // CL -e- 7/ // -2- // a i 0.0 0.5 1.0 (H-2R)/5 R/i;=0.2 - R/^=0.3 • R/^=0.5 — R/^=1.0 1.5 2.0 Figure 1. Reduced PM potential for several values of the reduced colloid radius R/^ and the selected value of the reciprocal adsorption length ^/a=0.1; A=^/RG. 3. Relaxation times of the colloid aggregation assisted by adsorbing and non-adsorbing polymers. As a final stage of the reported work, we have calculated the relaxation time t of the colloid aggregation for the case of dilute solution of colloids in polymer-solvent system. In line with the previous two stages, we have distinguished the cases of non-adsorbing and weakly adsorbing polymers. We have found that t decreases with increasing the volume fraction of adsorbing polymers and increases with increasing the volume fraction of non-adsorbing polymers at fixed colloid radius R. The above difference in the behavior of t as a function of the polymer volume fraction is attributed to different dependencies of the PM potential on the colloid radius and polymer volume fraction for the cases of adsorbing and non-adsorbing polymers. 4. Conclusions In summary, we have comparatively investigated the effect of purely entropic and adsorption interactions between polymers and nano-colloids on the polymer mediated interaction among these colloids. We have used the obtained results in order to derive the equation of state of the colloid-polymer-solvent system for the respective cases of polymer adsorption. In addition, we have derived the characteristic times of the colloid aggregation in dependence of the strength of the polymer adsorption onto the nano-colloids. The obtained results are compared with the available Monte Carlo simulations. Acknowledgements This research was supported in part by priority program SPP 1369 of the DFG. References [1] A. I. Chervanyov, Phys. Rev. E 2011, 83, 061801. [2] A. I. Chervanyov, G. Heinrich, J. Chem. Phys. 2011, 131, 4907. [3] P. G. Bolhuis, E. J. Meijer, A.A Louis., Phys. Rev. Lett. 2003, 90, 068304. S8-L26 Secondary motions in channel flows of glass-fiber-filled polypropylene melts Thomas Kopplmayr (1 )*, Rudolf Haftlacher (2 ) , Bernhard Plank (3 ) , Dietmar Salaberger (3 ) , Jurgen Miethlinger (1 ) (1) Institute of Polymer Extrusion and Building Physics, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria (2) Institute of Polymer Science, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria (3) University of Applied Sciences Upper Austria - Wels Campus, Stelzhamerstr. 23, 4600 Wels, Austria *thomas.koepplmayr@jku.at 1. Introduction In addition to their shear-thinning behavior, polymer melts are characterized by first and second normal stress differences, which are responsible for the occurrence of secondary motions. Viscoelastic flows through straight ducts exhibit secondary motions which cannot be explained solely by the first normal stress difference. Debbaut et al. [1] showed that these secondary motions originate from the combination of second normal stress difference and non-circular geometry. Thermoplastic materials such as polypropylene random copolymers are often filled with glass fibers to improve properties such as AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 stiffness, strength, and heat distortion temperature compared to their unfilled counterparts. However, because large aspect ratio fibers are dispersed in a polymer matrix, the rheological properties are complex. It is well known that a thermoplastic polymer filled with glass fibers with initially isotropic orientation exhibits, in the molten state, a viscosity overshoot when sheared in the parallel plate geometry of a rheometer. In this study, we varied the duration of different levels of pre-shearing in order to achieve an optimal orientation of the fibers parallel to the plates. Storage and loss moduli were measured accordingly. Numerical simulations were performed on the basis of a five-mode Giesekus model and were in good agreement with experimental observations. 2. Theory Let T denote the viscoelastic extra-stress tensor. If a discrete spectrum of N relaxation times is considered, T can be decomposed as follows: N T " IT (1) where T is the contribution of the i-th relaxation time to the viscoelastic stress tensor. For all individual extra-stress contributions T, we select the Giesekus constitutive equation [2] given by I + -- n = = 2nD, (2) where ^ and hi are the relaxation time and the partial viscosity factor, respectively, and the symbol V denotes the upper-convected time derivative operator and represents rates of change with respect to a convected coordinate system that moves and deforms with the fluid. In Eq. (2), ai are additional material parameters of the model which control the ratio of the second to the first normal stress difference. In particular, for low shear rates, we have a1 = -2N2/N1, where a1 is associated with the highest relaxation time l1. sym. Figure 1. (a) Experimental setup, (b) streamlines of secondary motions obtained by numerical simulation, and (c) comparison of experimental observations (top) with numerical surface tracking (bottom). 3. Experimental A Borealis RA130E polypropylene random copolymer intended for plumbing and heating applications was used as a base polymer. Three types of compounds were prepared and investigated in this study: compounds with (i) 100% short fibers (max. length 1.5 mm), (ii) 20% long (max. length 4.5 mm) and 80% short fibers, and (iii) 70% long and 30% short fibers. The rheological properties were measured using a stress- and strain-controlled rheometer equipped with an electrically heated thermostating unit. In order to investigate initial wall effects, we varied the duration of different levels of pre-shearing used to achieve an optimal orientation of the fibers parallel to the plates. The orientation of glass fibers was monitored using x-ray computed tomography (X-CT), and the measured viscosity was compared to results obtained from capillary slit rheometry. The effect of second normal stress difference was analyzed by observing the coextrusion of two batches of the same viscoelastic fluid, each with a different pigmentation, in a square duct. The development of secondary motions was observed by tracking the motion of the interface between both fluids. It has previously been found that the pigmentation does not affect fluid properties. The materials were extruded separately but at the same temperature (220°C). After the screws, they were merged in a feedblock at a well-controlled ratio, as shown in Figure 1. The black/white interface is almost horizontal when the material enters the channel and is deformed due to the occurrence of secondary motions towards the channel exit. 4. Results and discussion As shown in Figure 2, shear viscosity decreases with increasing levels of pre-shearing. In addition to the shear rate, the duration of pre-shearing also plays an important role, although its effect is less pronounced. An initial loading of 0.1 s-1 for 60 min turned out to be sufficient to reduce orientation effects to a level at which they can be ignored. Further pre-shearing damages samples, as indicated by a strong decrease in viscosity and results which cannot be reproduced. flSPM 2013 w w AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 We selected a discrete spectrum of five relaxation times lj ranging from 10"3 to 10 s. The corresponding partial viscosities hj were fitted on the basis of the dynamic properties G' and G", while the parameters a were selected on the basis of the shear viscosity. Using a single polymer melt with different pigmentation made observing the development of secondary motions in square die channels possible. In particular, the ways in which the black and white melt layers deformed under the action of second normal stress differences became visible. The experimental observations and their numerical counterparts were found to be in good accordance. X 1 r X ▼ X ▼ X ▼ * 10000G T V x x $ X T ▼ x ^ $ s, ▼ X o o no pre-shearing 10 min at 0.01 s" 15 min at 0.10 s 60 min at 0.10 s 60 min at 1.00 s 60 min at 1.00 s' ^ O sample damaged X X T X $ T X ■ 1 ▼ ž o o ■ o shear viscosity r) (co) □ storage modulus G'(ca) O loss modulus G"(co) A Giesekus 5-mode - 1 10 frequency, co (1 /s) frequency, to (1/s) Figure 2. (a) Variation of the degree of pre-shearing and (b) fitting rheological data with a five-mode Giesekus model. Acknowledgements Financial support by the Austrian Center of Competence in Mechatronics GmbH (ACCM) is gratefully acknowledged. ACCM is funded by the Austrian Government and the Provincial Government of Upper Austria as part of the COMET program. References [1] B. Debbaut, T. Avalosse, J. Dooley, K. Hughes, On the development of secondary motions in straight channels induced by the second normal stress difference: experiments and simulations, J. Non-Newtonian Fluid Mech. 1997, 69, 255 271. [2] H. Giesekus, A simple constitutive equation for polymer fluids based on the concept of deformation dependent tensorial mobility, J. Non-Newtonian Fluid Mech. 1982, 11, 69-109. Session 11: Advances in Polymer Analysis, Characterisation and Testing S11-L27 The impact of time, temperature and media on polymer selection for high demand applications Peter Guttmann*, Florian Roper, Gerald Pilz Montanuniversitaet Leoben, Chair of Materials Science and testing of Polymers *peter.guttmann@unileoben.ac.at 1. Introduction During the last decades polymeric materials, especially fiber-reinforced types, have been increasingly replacing metallic materials for designing structural components in high demand applications [1]. A number of polymer specific databases and tools (e.g. Cambridge Engineering Selector (CES [2]), UL-IDES [3], CAMPUS [4]...) are available to support engineers in proper materials selection. Because these tools mainly contain data for short term and standard conditions they are merely limited to a preselection of potentially suitable materials. To take account of application relevant conditions such as elevated temperatures and/or media influence appropriate materials testing methods have to be part of the materials selection process. This study focuses on the time and temperature dependent behaviour of technical high performance polymers, using an efficient approach for creep investigations in combination with dynamic mechanical analysis under the influence of ambient media. 2. Methodology and experimental As an initial step of materials selection for a specific application with high thermo-mechanical requirements combined with media influence, Cambridge Engineering Selector software tool [2] was used for materials preselection. The following selection criteria were exemplarily used (limits in brackets): high level of Young's Modulus (> 12 GPa), tensile strength (> 80 MPa) and fracture w w AUSTRIAN - SLOVENIA N POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 toughness (> 5 MPa*m0,5). Additionally a service temperature of 60 °C and general water durability (no degradation in materials performance expected after long term exposure [5]) as well as processability and materials price were considered. In order to get application relevant material information efficiently, a proper thermo-mechanical testing route was defined, containing water immersion of the test specimens at 60 °C until saturation (wet material state), dynamic mechanical characterization (DMA) and creep tests at elevated temperatures. The DMA experiments were performed in 3-point bending mode at various frequencies from 0.01 up to 100 Hz within a temperature range from -60 to 180 °C. For the creep investigations a special media cell was developed which allows the performance of creep test in water immersion. The stress level applied was 20 MPa at various temperature levels (T1=60 °C, T2=70 °C, T3=80 °C) using the stepped isothermal method (SIM) [6]. 3. Results and discussion The initial materials preselection process based on the Cambridge Engineering Selector software tool leads to Polyphthalamide with glass fibre reinforcement of 35 % (PPA-GF35), among other fibre-reinforced high performance polymers. In order to get application relevant information about temperature dependent materials performance, dynamic mechanical tests (DMA) were performed, both for dry and wet materials state. The dependency of the dynamic modulus E'(T, f) on temperature for various testing frequencies in the range from 0.1 to 100 Hz is shown in Figure 1, indicating a distinctive shift of the glass-transition temperature from 132 in dry to 57 °C in wet condition. Using the time/temperature superposition principle (TTS), which is based on the reduction of relaxation times at higher temperatures, the frequency dependent modulus data were plotted for various temperatures (measuring range) and shifted along the frequency axis to extend the resulting frequency range (extrapolation range). For this procedure also experimental temperature influences such as hysteretic and heating effects were regarded. The resulting modulus mastercurves for an application relevant temperature of 60 °C and the dry and wet materials state are shown in Figure 1. The frequency dependency of the dynamic storage modulus leads to a slight and almost linear decrease of the mastercurve for the dry materials state at the low frequency range. Modulus values of around 11 GPa were found for extrapolated test frequencies of 10"6 Hz. For the wet materials state the frequency dependency of the modulus mastercurve is distinctly stronger. Starting at modulus values of about 10 GPa the modulus decreases significantly to about 7 GPa for the low frequency range, mainly due to the low glass transition temperature of the wet materials state. In order to analyse the time dependent material performance for the wet state at a service temperature of 60 °C, creep tests were performed at elevated temperatures in water immersion. For test temperatures of 60, 70 and 80 °C and static tensile loading of 20 MPa the resulting creep curve is shown in Figure 2. After a subsequent calculation of the corresponding creep modulus curves, the curve segments for the higher test temperatures were shifted towards the long term range according to the time/temperature superposition principle. Also in this case the resulting mastercurve (s. Figure 2) shows a significant time dependent modulus decrease for the wet materials state corresponding to the glass-transition lowered to temperatures beneath 60 °C. (a) Dynamic Mechanical Analysis (DMA) Mode: 3-Point-Bending ial: PPA GF35 Mastercurve Reference Temperature: 60 °C Dynamic Mechanical Analysis (DMA) Mode: 3-Point-Bending Material: PPA GF35 Measuring Range -Wet (Water Content: 1,5 wt%) Temperature [°C] (b) Frequency [Hz] Figure 1. Dynamic Mechanical Analysis (DMA) for PPA-GF35: (a) Temperature dependency of dynamic modulus for various frequencies; (b) Modulus mastercurves for a reference temperature of 60 °C, determined by TTS principle out of (a) Creep Tests Mode: Tensile Material: PPA GF35 Stepped Isothermal Method ( Creep Tests Mode: Tensile Material: PPA GF35 Stepped Isothermal Method (SIM) Creep Stress: 20 MPa (a) Time [h] (b) Time [M Figure 2. Creep behavior for PPA-GF35 at 20 MPa: (a) creep strain ec vs. time t for test temperatures of 60, 70 and 80 °C; (b) creep modulus mastercurve for a reference temperature of 60 °C, determined by TTS principle out of (a). BLED, SLOVENIA, 3-5 APRIL, 2013 4. Conclusions For materials selection especially for high demand applications and media influence polymer specific properties such as time and temperature dependency of the elastic modulus have to be considered. Dynamic mechanical analysis represents an efficient method for the characterization of the thermo-mechanical behaviour of polymers at application relevant conditions. By DMA-tests at various frequencies and an extended temperature range, frequency and temperature dependent modulus data can be provided efficiently at suitable time ranges, even for preconditioned materials. Proper evaluation methods based on the time/temperature superposition principle can be used for the further evaluation of frequency-dependent behaviour. Furthermore the presented exemplary material characterization of PPA-GF35 shows significant creep behaviour at 60 °C and wet material state. Hence, DMA and Creep tests are efficient methods for the determination of application relevant material properties which are not available in ordinary data sources but which are decisive for material selection. Acknowledgements The research work was performed at the Chair of Materials Science and Testing of Polymers in cooperation with the Materials Center Leoben Forschung GmbH and the ANDRITZ AG. Financial support by the Austrian Federal Government (in particular from the Bundesministerium fur Verkehr, Innovation und Technologie and the Bundesministerium fur Wirtschaft, Familie und Jugend) and the Styrian Provincial Government, represented by Osterreichische Forschungsforderungsgesellschaft mbH and by Steirische Wirtschaftsforderungsgesellschaft mbH, within the research activities of the K2 Competence Centre on "Integrated Research in Materials, Processing and Product Engineering", operated by the Materials Center Leoben Forschung GmbH in the framework of the Austrian COMET Competence Centre Programme, is gratefully acknowledged. References [1] M.F. Ashby, Materials Selection in Mechanical Design, 4th ed., Elsevier; Butterworth-Heinemann, Amsterdam, Boston, Burlington, Mass, 2011. [2] CES Selector 2012 software, Granta Design Limited, Cambridge, UK, 2011. [3] UL IDES, URL: http://www.ides.com/. [4] CAMPUS, URL: http://www.campusplastics.com. [5] D. Cebon, M.F. Ashby, C. Bream, L. Lee-Shotham: CES Selector 2012 User's Manual, Release 1: Granta Design Limited, Cambridge, UK, 2011. [6] ASTM D6992-03. Standard Test Method for Accelerated Tensile Creep and Creep-Rupture of Geosynthetic Materials Based on Time-Temperature Superposition Using the Stepped Isothermal Method, ASTM International, West Conshohocken, PA, 2009. S11-L28 Comparison of crack growth kinetics in different polypropylene grades using linear elastic fracture mechanics Florian Arbeiter (1 )*, Gerald Pinter (1 ) , Frank Andreas (2 ) (1) Chair of Material Science and Testing of Polymers, Otto-Glockel-Str. 2, 8700 Leoben, Austria (2) Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, Austria *Florian.Arbeiter@unileoben.ac.at 1. Introduction Polypropylene is a widely used thermoplastic polymer. Due to its manifold applications extensive knowledge of material properties is necessary. Especially in structural applications it is of utmost importance to regard long term mechanisms which can lead to unexpected failure. Crack initiation and Slow Crack Growth can cause this kind of failure over long time frames and must not be neglected when considering possible applications for the material. The high local ductility of Polypropylene, however, makes it very hard to determine long term properties, such as crack initiation and growth in feasible time frames. Therefore faster methods are needed to describe these vital material properties. One of the possibilities is the use of Linear Elastic Fracture Mechanics (LEFM). It can be used to determine crack kinetics of materials. Depending on the crack kinetics, material parameters can be derived and used to calculate life times of actual structural applications under similar loading conditions. Crack initiation is not considered in this approach and acts as an additional safety factor. The specimens used in this work are Cracked Round Bar Specimens (CRB) which provide a strong constraint at the notch root and are therefore able to induce brittle crack growth even in rather ductile materials such as Polyethylene and Polypropylene. 2. Theory The proper application of LEFM requires global loads which are in the range of linear viscoelasticity and that there are only small and localized plastic deformations at the crack tip [1]. The distribution of stress around the crack tip can then be described with the Stress Intensity Factor (K). K is dependent on the global loading s, the general crack length a and a geometric factor Y which describes the development of K in relation to specimen geometry and crack length as can be seen in equation 1 . The factor K is usually specified according to the loading condition [2]. All specimens in this work are tested under pure tensile load and marked BLED, SLOVENIA, 3-5 APRIL, 2013 with I. K, = o-Ja-Y Equation 1. Generalized Stress Intensity Factor under pure tensile load (= mode I) with the crack length a, global load s and the geometric factor Y In a double logarithmic diagram crack growth over time can be plotted as a function of KI. According to theory there are three different areas in these plots. The first area is the so called threshold. Below this load value the crack does not start to grow. Increasing the load leads to crack initiation and stable crack growth which marks the second area. The third area is the unstable crack growth. At this loading level the crack growth rates increase drastically and the specimen fractures abruptly. The constant slope of the second area can be described by equation 2 where A and m are material constants and da/dt is the crack extension per time frame [3]. When conducting cyclic testing to shorten testing times da/dt is usually replaced by da/dN where dN is the number of cycles needed for the crack extension da. Additional the Stress Intensity Factor K is replaced by DK which considers the cyclic loading. Another important factor when conducting cyclic testing is the loading ratio Fmin/Fmax which is 0.1 in the current work and therefore results in DK = Kmax - Kmin = Kmax'0.9 [4, 5]. Equation 2. Crack Growth Kinetics with the material parameters A and m, the Stress Intensity Factor KI and crack extension da over passed time dt 3. Experimental The examined materials can be seen in Table 1. All three are made of Polypropylene with different reinforcements and or base material compositions. Materials were chosen according to demands in real application. All cyclic tests were performed on servo-hydraulic fatigue testing machines (MTS Table Top (MTS Systems GmbH, Germany)). The frequency for the test was 5 Hz to minimize increase of temperature due to hysteretic heating while testing. Table 1. Composition of all examined materials Material Polymer Reinforcement PP 1 PP-Block ~ 50% Talc PP 2 PP-Block / PP-Homo ~ 50% Talc PP 3 PP-Blend ~ 20% Wollastonite Actual crack length a(N) during the test could not be observed optically and was therefore calculated by means of a compliance calibration method [6]. The geometric factor Y = f(b/r) which is mentioned in Equation 1 was calculated according to Benthem and Koiter and is shown in Equation 3 [7]. KS=H1+HS+ž ■ ©2 -0363 • ©3+°-731 ■ ©4 Equation 3. Calculation of the geometric factor for CRB-Specimen according to Benthem and Koiter where r is the radius of the specimen and b the current concentric crack length 4. Results and discussion Using the compliance method mentioned earlier it was possible to generate crack growth kinetic data for all three materials. In Figure 1a the kinetics for all materials can be seen for the loading conditions of R=0.1 and f=5 Hz. According to LEFM theory the applied load is irrelevant for the results as long as the requirements of LEFM which are explained in the Theory section are met. In Figure 1b crack kinetics data for the same material are shown for different loading levels. Lines of both tests coincide in the second area where stable crack growth is measurable and therefore indicate the applicability of LEFM for this test. At higher values of DK| the slopes change which is an indication of high local plasticity which disagrees with the requirements of LEFM. AUSTRIAN - SLOVENIAN POLYMER MEETING BLED, SLOVENIA, 3-5 APRIL, 2013 Crack Kinetics for PP f=5 Hz, T=23°C, R=0.1 • PP 1 AK =0 676 MPam ■ PP 2 AK=0 718 MPam ▲ PP 3 AK =0 641 MPam Linear Fit of PP 1 ----Linear Fit of PP 2 Linear Fit of PP 3 0,8 0,9 AKi [MPam05] ¥ • PP 1 AK=0.676 MPam O PP 1 AK=0.702 MPam05 Linear Fit of PP 1 AK=0.676 MPam0: -----Linear Fit of PP 1 AK=0.702 MPam05 0,9 AK, [MPam05] Crack Kinetics for PP f=5 Hz. T=23°C. R=0.1 Figure 1. Comparison of crack growth kinetics of all three materials (a) and validation of applicability of LEFM by use of different loading levels for the test (b) Acknowledgements The research work of this publication was performed at the Chair of Materials Science and Testing of Polymers (University of Leoben, Austria) within the framework of the FFG program of the Austrian Ministry of Traffic, Innovation and Technology and the Austrian Ministry of Economy, Family and Youth with contributions of the Osterreichisches Forschungsinstitut fur Chemie und Technik (Austria), Martin-Luther-Universitat Halle-Wittenberg (Germany) and the Polymer Competence Center Leoben GmbH (Austria) References [1] Lang, R.W.: Applicability of linear elastic fracture mechanics to fatigue in polymers and short-fiber composites (1984) [2] Hertzberg, R.W.: Deformation and fracture mechanics of engineering materials, 4th edn. J. Wiley & Sons, New York (1996) [3] Paris, P., Erdogan, F.: A critical analysis of crack propagation laws. Transactions of the ASME. Journal of Basic Engineering 1963(85), 528-534 [4] Broek, D.: Elementary engineering fracture mechanics, 3rd edn. Martinus Nijhoff; Distributed by Kluwer Boston, The Hague, Boston, Hingham, Mass (1982) [5] Anderson, T.L.: Fracture mechanics. Fundamentals and applications, 3rd edn. CRC, Taylor & Francis, Boca Raton [u.a.] (2005) [6] Frank, A., Freimann, W., Pinter, G., Lang, R.W.: A fracture mechanics concept for the accelerated characterization of creep crack growth in PE-HD pipe grades. Engineering Fracture Mechanics 76(18), 2780-2787 (2009). [7] Benthem, J., Koiter, W. (eds.): Method of Analysis and Solutions of Crack Problems, 3rd edn. (1973) S11-L29 Ion mobility mass spectrometry, an enabling technology for polymeric characterisation Matthew Kennedy* Waters Corporation, Simonsway, M22 5PP, Manchester, United Kingdom *matt_kennedy@waters.com 1. Introduction Polymeric materials are inescapable in our modern societies and cover a broad range of applications, in areas such as automobiles, textiles, packaging, medicine and pharmacy, to name just a few. The increasing complexity of such applications has generated a requirement for highly complex polymeric materials. Accurate and detailed polymer characterisation is therefore vital to this process. Recently, a great deal of time and effort has been invested in polylactide research due to their bio-compatible and biodegradable nature [1]. The utility of both mass spectrometry (MS) and ion mobility spectroscopy (IMS) to characterise polymeric materials is well documented; however, although the combination of these techniques provides significant advantage, compared to the individual techniques. It should be noted, significant limitations must be overcome to produce a viable analytical tool. As a result it is only recently that a commercial IMS-MS instrument has been available (ASMS 2006). This instrument utilises alternative technologies that overcome the main limitations of a classical IMS-MS system but retains the benefits of the union [2]. Such an instrument is ideal for characterising complex polymeric materials such as polylactide. BLED, SLOVENIA, 3-5 APRIL, 2013 2. Theory The inclusion of ion mobility functionality along with mass spectrometry provides an additional, orthogonal mode of separation, which affords the analyst increased peak capacity. Ions can be separated by their mass, their shape, and also their charge. 3. Results and discussion Polylactide samples were introduced to the ElectroSpray (ESI) source via direct infusion. Due to the nature of ion formation in ESI, ions with different charge states are generated. This phenomenon makes data analysis extremely complicated. By utilizing the mobility separation, it is possible to deconvolute different charge states within the polymeric ion series, thus simplifying data handling. We are also able to show that the folding patterns observed in the travelling wave region (IMS) of the instrument is consistent with published literature based on theoretical calculations and experiments carried out on classical IMS devices (a linear drift tube) [3] 4. Conclusions In this work, we demonstrate that the additional mode of separation offered by ion mobility can be used to aid the characterisation of polymeric materials as well as provide a greater understanding of the 3-dimensional structure of polymers. References [1] J Am Soc Mass Spectrom 2010, 21, 1159-1168 [2] K.Giles, J.Wildgoose, J.Langridge, I. Campuzano, Int.J.Mass.Spectrom. 2010, 298, 10-16 [3] Chem. Eur. J. 2011, 17, 9738 - 9745 S11-L30 MALDI (matrix-assisted laser desorption ionization) and ES(I) (electrospray (ionization) ) techniques for the characterization of natural (latex surfaces, gelatin nano particles and polysaccharides) and synthetic (UHMW-PE) polymers Martina Marchetti-Deschmann (1 ), Sophie Frohlich (1 ) , Angela Lehner (1 ) , Victor U. Weiss (1), Wladek Szymanski (2 ), Matthew A. Kennedy (3), Guenter Allmaier (1 )* (1) Vienna University of Technology, Institute of Chemical Technologies and Analytics, Getreidemarkt 9/164, A-1060 Vienna, Austria (2) University of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090 Vienna, Austria (3) Waters, Atlas Park, M22 5PP Manchester, UK *guenter.allmaier@tuwien.ac.at 1. Introduction In the characterization of polymers and polymeric nano particles of synthetic origin as well as of natural sources molecular weight determination, size determination, heterogeneity of the sample and finally primary structural elucidation are the starting point in any case. During the last decades several techniques based on electrospraying (ES) combined with charge reduction of aqueous polymer solutions, electro spray ionization (ESI) of soluble polymer solutions and matrix-assisted laser desorption ionization (MALDI) of insoluble (directly from polymeric solids) as well as soluble polymers were introduced. These techniques allowed the generation of gas-phase singly or multiply charged species even in size range beyond 5 nm and in the molecular weight range above 1 million Dalton. The so generated ionic species were transferred to different separation devices, namely time-of-flight (TOF) analyzer, quadrupole-reflectron TOF (QRTOF) analyzer with and without prior ion mobility (IM) separation and high flow differential mobility analyzer (DMA). The goal of the presentation is to show achievements and also limitations of the mentioned combination of techniques for the first characterization steps of synthetic and natural polymers [1, 2]. 2. Experimental Natural latex used in medical glove production [3] and ultrahigh molecular weight (UHMW) PE used as human implants were used as solid material for mass spectrometric imaging (IMS) by means of UV-MALDI. Specific sample preparation protocols were used to perform direct desorption/ionization from the MALDI-matrix covered solid samples. The MALDI mass spectrometers applied were either a Synapt HDMS or G2 QRTOF (Waters, Manchester, UK) and a Axima CFR or Axima Tof2 (Shimadzu Kratos Analytical, Manchester, UK). For ESI mass spectrometry of soluble polymeric materials (e.g. gelatin or intact virus nano particles) a Synapt G2 QRTOF (Waters, Manchester, UK) was selected with a 32 kDa RF quadrupole device. The combination of ES with a Po-201 source (for charge reduction) and a high flow DMA followed by a condensation particle counter (CPC) as detector (independent of the chemical composition of the sample) is called MacroIMS (ion mobility spectrometer) or GEMMA (gas-phase molecular mass analyzer) provided by TSI Inc (Shoreview, MI, USA). This device was used for all analysis were the samples (e.g. gelatin, intact virus, polysaccharides) were soluble in aqueous solutions or suspensions [1, 2]. BLED, SLOVENIA, 3-5 APRIL, 2013 3. Results and discussion We will show the results of the analysis of challenging polymeric samples - direct analysis (Imaging MS by MALDI) of latex [3] and UHMW-PE used in the medical field, i.e. the distribution of small organic and biological molecules on the polymeric surfaces as well as the structural characterization of them by tandem MS. Limitations and outlooks of these approaches will be presented. For the synthetic gelatin nano particles, intact virus particles and polysaccharides, all dissolved or suspended in aqueous solution systems ES with charge reduction and DMA analysis will be presented up to a particle size of 40 nm and a molecular mass of several mega Daltons. Successful attempts to use ESI in combination with a QRTOF mass analyzer (32 kDa RF quadrupole can do this only) to analyze the identical samples will be presented, too. 4. Conclusions What we want to present is that new techniques and unusual combination of techniques are allowing to bridge the existing gap between analysis of small polymeric molecules and of high molecular mass polymer-based nano particles. Analytical characterization is essential before these materials are entering the field of applications. This is of particular importance due to the fact that more and more synthetic or semi-synthetic materials (e.g. polymer (PE or latex)-based implants) and nano particles (e.g. drug delivery) are used in various fields of nanotechnology Acknowledgements This work was supported by a grant of the Austrian Science Foundation (TRP29-N20 to WS and GA). Further we thank D. Blaas (Medical University, Vienna, Austria) for providing the virus samples. References [1] G. Allmaier, C. Laschober and W. Szymanski, J. Am. Soc. Mass Spectrom. 2008, 19, 1062-1068. [2] R. Muller, C. Laschober, W. Szymanski and G. Allmaier, Macromolecules 2007, 40, 5599-5605. [3] M. Marchetti-Deschmann and G. Allmaier, J. Mass Spectrom. 2009, 44, 61-70. Session 9: Polymer Degradation and Stabilization S9-IL31 Odor perception and polymer degradation Anders Hoglund (1 )*, Ann-Christine Albertsson (1 ), Anna Lindqvist (2 ), Birgitta Berglund (2,3) (1) KTH Royal Institute of Technology, Department of Fibre and Polymer Technology, Teknikringen 56-58, SE-100 44 Stockholm, Sweden (2) Stockholm University, Department of Psychology, Frescati Hagvag 8, SE-106 91, Stockholm, Sweden (3) Karolinska Institutet, Institute of Environmental Medicine, P.O. Box 210, SE-171 77, Stockholm, Sweden *anhog@kth.se 1. Introduction Modern instrumental analytical methods have provided a good understanding of polymer degradation, both during early and later stages of degradation. The straight-forward approach is to subject polymer samples to natural or accelerated degradation environments and measure one or several polymer properties as a function of time. An alternative method is to correlate the 1 degradation products formed during ageing to simultaneous molar mass changes and changes in mechanical properties. Such a correlation allows the assignment of certain indicator products to predict the degree of degradation of polymers. Indicator products can also be used to show the degree of degradation of chemically cross-linked networks,2 to identify surface grafting of polymers,3 or to discriminate different polymer types.4 The indicator products are identified after extraction and subsequent GC-MS analysis. Drawbacks with these procedures include limited instrumental detection limits, the need for careful sample taking, proper method development, and high instrument costs. Our main aim is to develop a rapid and straight-forward method to detect polymer degradation. The hypothesis is that the odorous volatile compounds released from the polymers during ageing can be used as a link to relate odor quality to polymer degradation. To verify this, odor intensity measures were compared with GC-MS and tensile testing results. In addition, pure compounds of the degradation products were studied as binary and higher order mixtures in order to reveal key information about the human olfactory code. 2. Theory When exposed to e.g. UV-light or heat, polymers degrade. This results in a deterioration of material properties and formation and release of degradation products. These substances are subsequently emitted to the indoor air were they may affect human health. In addition, the degradation products may also be useful to reveal information about the status of the polymer they originate from. The use of odor perception as a detection method has been proven useful in other research fields. Odor perception is widely used in the wine industry to discriminate and categorize the wines.5 Changes in wine odor profiles during oxidative ageing are also LED. SLOVENIA. 3-5 APRIL. 2013 studied with parallel odor perception and GC-MS.6 In medicine, disease-specific compounds have been shown to be useful for olfactory diagnosis.7 A relatively well-known example is the acetone-like breath of diabetes patients resulting from ketone compounds generated by fatty acid metabolism. If successful for detecting wine oxidation and various diseases, odor perception may also be useful for detecting polymer degradation. 3. Experimental Strips of Polyamide 66 (PA66) were thermo-oxidized at 90 °C for 12, 72, 168, and 288 hours. Odor stimuli consisted of aged polymers, two to five-order mixtures of PA66 degradation products, and blanks. Each subject measured odor intensity, odor similarity, and odor pleasantness/unpleasantness by free magnitude estimation. Arithmetic means for the group were calculated. The low molar mass products from the polymer samples were extracted by HS-SPME and subsequently analyzed by GC-MS. Tensile testing of the polymer materials were performed on an Instron 5566, the thermal properties of the polymers were determined with a DSC, and FTIR spectra of the thermo-oxidized polymer materials were also recorded. 4. Results and discussion The perceived odor intensity of PA66 during the initial stages of the degradation (up to 72 h) was relatively low but increased approximately 150% after 168 h (Figure 1, left).8 In parallel, a total of eight degradation products increased in extracted amount with increased degradation time. Five of these were identified as odorous in the odor experiments: pentanoic acid, 2-metyl-pyridine, butanamide, pentanamide, and dibutyl phthalate. Both tensile strength and elongation at break decreased with increased degradation time (Figure 1, right). This deterioration in mechanical properties was continuous. However, it was not until after 168 hours that a significant deterioration in mechanical properties was observed. Interestingly, this deterioration in mechanical properties coincided with the 150% increase in perceived odor intensity of the aged materials and also with the increase in extracted amounts of degradation products. During the same time period, negligible changes in thermal and surface properties of PA66 were observed. Odor perception was, thus, demonstrated to be a useful tool to detect polymer degradation at an early stage. Binary and higher-order mixtures of the PA66 degradation products were also studied.9 The perceived odor qualities of the binary mixtures were intermediary vectors relative to their single component-odor vectors in a three-component principal components analysis (PCA). Three of the PA66 degradation products and their odor qualities contributed profoundly to their binary mixtures: the "floral/fruity" 2-pentylcyclopentan-l-one, the "sharp/cheese-like" pentanoic acid and the "minty" cyclopentanone but in fewer cases. The "ether-like" 2-methyl pyridine and the "nutty" butanamide had much less influence. Odor similarity was shown to be caused by odor quality, rather than odor intensity. The profoundly contributing degradation products formed distinct clusters of odors and were therefore interpreted to be key degradation products of PA66. In contrast to the binary mixtures, the higher-order mixtures created new odor qualities which were completely different and untraceable to their various parts as perceived alone. 100 'in 80 50 100 150 200 250 300 350 Degradation time [h] 60 §5°