494 Acta Chim. Slov. 2021, 68, 494–504 Kravanja et al.: Degradation of Plasticized Poly(1-chloroethylene) ... DOI: 10.17344/acsi.2020.6464 Technical paper Degradation of Plasticized Poly(1-chloroethylene) Waterproofing Membranes used as a Building Material Gregor Kravanja,1,2* Andrej Ivanič2 and Samo Lubej2* 1 University of Maribor; Faculty of Chemistry and Chemical Engineering; Laboratory of separation processes and product design, Smetanova ul. 17, 2000 Maribor, Slovenia 2 University of Maribor, Faculty of Civil Engineering, Transportation and Architecture, Smetanova 17, 2000 Maribor, Slovenia * Corresponding author: E-mail: gregor.kravanja@um.si and samo.lubej@um.si Received: 10-23-2020 Abstract In the present work, both unused plasticized poly(1-chloroethylene) membranes and membranes taken from a flat roof area were comprehensively analysed. First, tensile strength and elongation at breaking points were determined, followed by measurements of wettability. Secondly, morphological changes were analysed using scanning electron microscopy (SEM). To study chemical changes in aged membranes, Fourier transform infrared spectroscopy (FTIR) analysis in the attenuated total reflection mode (ATR) was used. Finally, thermogravimetric analysis and differential scanning calorim- etry (TGA-DSC) were performed simultaneously to study thermal degradation. The results show obvious changes in the mechanical, physical and chemical properties of membranes caused by plasticizer loss. Surface microstructure becomes stiffer, which leads to contractions and the prevalence of voids. In cross-sectional area, average thickness values decrease. Due to the degradation of the plasticized waterproofing membranes, the roofing area had to be completely replaced. Keywords: degradation; waterproofing membranes; plasticized PVC; SEM; FTIR; TGA-DSC 1. Introduction Poly(1-chloroethylene) (PVC) is formed by the po- lymerization of vinyl chloride monomers. It is one of the most commonly used thermoplastics in construction, au- tomotive, electrical parts and packaging.1 The properties of PVC can be significantly improved by adding plasticiz- ers to make it more flexible and durable, which greatly ex- pands its applications.2, 3Plasticized PVC membranes are among the most commonly used waterproofing materials for roofing and geotechnical applications. However, prac- tice shows that roofing membranes undergo chemical and physical changes when exposed to the combined effects of heat from solar radiation, near ultraviolet radiation, at- mospheric oxidation, moisture and air pollution over long periods of time.4 As a result, plasticizers escape from the membranes through evaporation, leaching, and migration into other materials, causing significant changes in materi- al flexibility, hardness, mass and elasticity.5 Despite extensive research in recent years in the field of testing of waterproofing membranes, there is still a shortage of specific studies on the durability, repairability and performance of such materials in roofing applications. The performance of plasticized PVC membranes has been evaluated by Dunn et al.6 who exposed the membranes to different climatic conditions for 4.5 years and reported the loss of plasticizer by evaporation. Similarly, Audouin et al.7 showed that increased temperature affects the mi- gration of plasticizer from the membranes. They analysed the mass loss kinetics of plasticized PVC between 85 °C and 120 °C. Ito and Nagai8 investigated the influence of ar- tificial ageing conditions on plasticized PVC. They found obvious changes in mechanical properties and microstruc- ture through the thickness difference caused by plasticiz- er loss. Beer at al.9 investigated the long-term behaviour of plasticized PVC at different locations in Europe and North America. They confirmed reduced low-temperature flexibility and elongation at break points following plasti- cizer migration. Blanco et al.10 investigated the long-term behaviour of high-density polyethylene (HDPE), ethyl- ene-propylene-diene monomer (EPDM) and plasticized PVC membranes, and reported that the shear strength of 495Acta Chim. Slov. 2021, 68, 494–504 Kravanja et al.: Degradation of Plasticized Poly(1-chloroethylene) ... joints remained relatively unaffected by ageing despite the loss of plasticiser. Kositchaiyong et al.11 studied anti-fungal performance and mechanical-morphological properties of PVC and wood/PVC composites under the influence of soil and UV light, and concluded that UV weathering reduced the antifungal performance of the material from 81.4% to 28.3%. Recently, environmental and economic comparisons of the life cycle performance of bituminous, synthetic, liquid and cement-based membranes suitable for flat roofs were reviewed by Goncalves et al.12 Paolini et al.13 investigated twelve roofing membrane products made of modified bitumen, PVC and polyolefin with dif- ferent spectral reflectances in terms of energy demand for building cooling. It was found that weathering, soil- ing and biological growth significantly affect their solar reflectance and thus increase the energy consumption for air conditioning. Furthermore, as shown in our previous study, natural ageing under high humidity and thermal fluctuations can strongly influence the surface morphol- ogy and chemical composition of fibrous insulation mate- rial covered with plasticized PVC.14 A probable reason for the deterioration of the insulation was the damaged wa- terproofing PVC membrane. To ensure a fully functional and repair-free lifetime of a building, the degradation and durability estimation of covering water-repellent PVC-P membranes must be considered. The objectives of this study were to evaluate the basic properties of plasticized PVC membranes and to measure the level of degradation by comparing unused membranes and weathered (aged) membranes from a flat roofing area. To the best of the authors knowledge, little information was reported in the literature on plasticized PVC membranes re- inforced with a polyester mesh that can be used for mechan- ically fixed roof systems above thermal insulation. First, the mechanical properties and wettability of these membranes were comprehensively evaluated. Secondly, morphological changes in the microstructure were evaluated to determine the thickness and prevalence of voids that were probably created by plasticizer loss. To explain such plasticizer loss in the material, chemical changes were identified and quanti- fied. Finally, the thermal stability of the samples was exam- ined to determine the degree of thermal degradation 2. Material and Characterization Methods New plasticized PVC membranes and membranes from the flat roof area, which are about 10 years old, were comprehensively analysed in a laboratory using various techniques. 2. 1. Samples from the Case Study 1.2 mm thin Standard Grey RAL 7047 plasticized PVC membranes reinforced with polyester mesh (Flagon Figure 1. Plasticized PVC waterproofing membranes were taken from a flat industrial roof located in Slovenia, Central Europe (a, b) Extraction at sampling location 1 (c). Naturally aged and locally damaged plasticized PVC membrane (d). 496 Acta Chim. Slov. 2021, 68, 494–504 Kravanja et al.: Degradation of Plasticized Poly(1-chloroethylene) ... SR, Soprema, Italy) were obtained from the unvented roof of an industrial building located in Slovenia, Central Eu- rope, which is characterized by a Cfb climate zone (Figure 1 a,b,c). Membranes are made of 51% pure PVC, 46% ad- ditives and 3% reinforcing material. The roof construction consisted of several layers: on top, a 1.2 mm thick plas- ticized PVC membrane; below, a 200 mm thick layer of thermal insulation with a density of 150 kg/m3, followed by a 0.3 mm thick vapor barrier and trapezoidal sheet met- al cladding anchored in steel roof beams (Appendix 1). An inspection revealed that the waterproofing membranes were damaged at several points where the photovoltaic modules were installed; the damage was visible as star- shaped cracks (Figure 1. d). Samples exposed to natural outdoor weathering were taken from various sampling locations, as shown in Appendix 2. Location 1 is an area with many visible star- shaped cracks on the surface of membranes. Location 2 is an area where a strong colour variation of the membranes was observed. Location 3 is a softening roofing area where a significant deterioration in the strength of the insulation has been observed. Plasticized PVC membranes were tak- en from each of these roofing areas, immediately wrapped in polyethylene, and transported to the laboratory for fur- ther analysis. Plasticized PVC membranes are produced by caste spreading, whereby a spreading head applies a substrate of a liquid-viscosity raw material called “plastisol”. The spreading and gelation process is repeated four times, cre- ating a membrane of four differently formulated layers. Between the second and third layers an inner reinforcing layer of polyester mesh is inserted. This process creates a molecular bond between the layers, resulting in a homoge- neous, elastic, single-layer membrane.15 2. 2. Mechanical Testing The mechanical performance of new, unused PVC membranes and aged membranes from the roof area was measured with a Zwick/Roell Z010 universal testing ma- chine according to standard EN 12311-2. The length of the samples was 200 mm and width 50 mm. At an elongation of 1% and 2%, the secant modulus of elasticity was meas- ured at a cross-head speed of 1.25 mm/min. After exceed- ing a deformation of 2%, samples were measured with a test cross-head speed of 200 mm/min until they broke. All specimens were tested in longitudinal and transverse direc- tions using the same test method under laboratory condi- tions T = 393.15 ± 2 K, RH (relative humidity) = 50 ± 5 %. 2. 3. Contact Angle Measurement The wettability of plasticized membranes was as- sessed with an exact experimental procedure. Droplets of milli-Q water (a specific resistance of 18.2 µΩ) with exact sizes of 10 µl were formed on a membrane with a micropi- pette. Droplets were filmed with a Basler Aca1300-200um digital camera equipped with a Basler Premium Lens with C-mount, connected to a computer using the OpenDrop algorithm to calculate the contact angles.16 To avoid opti- cal aberrations and the fake reflections from other sources that can occur at the drop edge, the drop of was lit from the opposite side with a diffusion light, which was achieved by placing a glass diffuser between the light source and the sessile drop. The undesired effect of drop oscillation was minimized by using an anti-vibration table. 2. 4. Thickness Evaluation, Surface Morphology and Chemical Characterization The thickness evaluation and morphological chang- es in aged membrane microstructure were scanned using ESEM (Environmental Scanning Electron Microscopy) Quanta 200 3D (FEI Company, Hillsboro, OR). Chemical modifications were identified and quantified using Fouri- er Transform Infrared Spectroscopy (FTIR) analysis on a Bruker Tensor 27 DTGS spectrometer in attenuated total reflection (ATR) mode between 4000 and 450 cm−1 with an average of 32 consecutive scans and a resolution of 4 cm−1. 2. 5. Low-temperature Flexibility Low-temperature flexibility is an important mem- brane property, especially during the application phase. Normally, the flexibility of membranes decreases signifi- cantly along with the surrounding temperature.9 A test of low-temperature resistance was carried out according to the SIST EN 495-5 standard. This European Standard specifies a method for the determination of the behaviour of plastic and rubber sheets for waterproofing to folding after expo- sure at a low temperature. The examined samples were fold- ed at 180° and conditioned for 12 h at low temperatures in a chamber. The occurrence of cracks in the samples indicates that the material is not resistant to low temperatures. 2. 6. Thermal Degradation Thermogravimetric analysis and thermal transition of material samples were carried out using a TGA/DSC (Differential Scanning Calorimetry) instrument (Mettler Toledo). The investigated material was placed in separate vials and heated in an N2 atmosphere at a rate of 20 K/ min from 298 K to 1273 K. Mass loss was measured as a consequence of thermal degradation of membrane layers. 3. Results and Discussion 3. 1. Mechanical Performance The maximum tensile strength in MPa (σ) and the elongation at break in % (ε) were determined for samples 497Acta Chim. Slov. 2021, 68, 494–504 Kravanja et al.: Degradation of Plasticized Poly(1-chloroethylene) ... Figure 2. Tensile strength and elongation at break (load/strain curves) for new plasticized PVC membrane samples tested longitudinal (left) and transverse (right) directions at conditions: T = 393.15 ± 2 K, RH (relative humidity) = 50 ± 5 %. Figure 3. Tensile strength and elongation at break (load/strain curves) for aged, plasticized PVC membrane samples tested longitudinal (left) and transverse (right) directions at conditions: T = 393.15 ± 2 K, RH (relative humidity) = 50 ± 5 %. after 10 years of use and the values were compared with those of new samples (Figures 2 and 3). Three samples were tested from each sampling location. As can be seen in Figure 3, there is a small variation in tensile strength in the longitudinal direction of aged membranes. It appears that the polyester mesh is well encapsulated within the mem- brane matrix and has not degraded over time. In addition, there is a tendency for tensile strength to increase with age, as the membrane loses flexibility over time.9 Similar obser- vations were made in a study by Blanco et al.10, where both load and tensile strength in longitudinal and transversal directions were evaluated for 35-year-old geomembranes with reinforced polyester. On the other hand, the strength of aged membranes decreases in the transverse directions compared to the strength of a new membrane. As shown in Table 1, aged membrane samples showed a shorter elongation at break than that of the new membrane. This indicates a loss of flexibility caused by natural aging under high humidi- ty and thermal fluctuations. The deterioration in elastic properties is caused by the loss of plasticizers as a result of a long period of combined exposure to heat from solar 498 Acta Chim. Slov. 2021, 68, 494–504 Kravanja et al.: Degradation of Plasticized Poly(1-chloroethylene) ... Table 1. Tensile strength and elongation at break. Sample σ (MPa) ε (%) σ (MPa) ε (%) longitudinally transversely New 20.23 22.36 19.17 20.01 18.68 44.54 19.27 20.51 20.43 22.16 18.17 19.28 Location 1 24.94 19.34 17.88 17.48 25.16 18.79 18.57 17.16 22.53 16.76 17.54 16.83 Location 2 23.90 18.36 15.91 17.21 23.55 17.31 15.04 15.49 23.70 18.39 16.12 16.51 Location 3 24.01 19.96 16.26 18.96 24.26 19.99 14.38 17.73 25.27 19.96 15.29 16.29 Table 2. Time-dependent contact angles of water droplets on new plasticized PVC membranes. CA 69.4°±1.1° 68.2°±1.5° 66.5°±0.8° 65.11°±0.5° t (s) 10 s 30 s 120 s 180 s Table 3. Time-dependent contact angles of water droplets on naturally aged and damaged plasticized PVC membranes (location 1). CA 56.1°±2.5° 16.5°±4.5° / / t (s) 10 s 30 s 120 s 180 s radiation, ear-ultraviolet radiation, atmospheric oxida- tion, humidity and air pollution.17 It was found that the influence of plasticizer content has a certain influence on elongation, but a mixed influence on the tensile strength of membranes reinforced with polyester mesh. Despite suf- ficient tensile strength, the wettability properties of these membranes were strongly influenced by age. plasticized PVC membranes remain almost constant with- in 180 seconds and have a significantly higher initial con- tact angle compared to the aged samples. In contrast, the contact angle for aged membranes is significantly reduced from 56.1°±2.5° at 10s to 16.5°±4.5° at 30 seconds and be- comes zero after 120 seconds (Table 3, 4 and 5). Despite the good mechanical performance, the water repellence of these membranes is strongly impaired. Increasing the hy- drophilicity of the aged membrane increases the unwant- ed water permeability and can cause damage in other roof layers.18 3. 3. Surface Morphology As mentioned above, the distribution and loss of plasticizer in the membrane can play an important role in tensile strength and elongation at break as well as in wet- tability properties. Change in surface of membranes that may result in the loss of plasticizer was also demonstrated by observation of micrographs from scanning electron mi- croscopes (SEM). 3. 3. 1. Microstructure Microphotographs of new and aged membranes tak- en by SEM show significant differences between them. As shown in Figure 4, new membranes have a smooth sur- face, without cracks. Locally, only the grains of filler can be observed. In contrast, aged membranes that have been exposed to natural weathering show irritated surfaces with many cracks, agglomerates and craters as a result of plas- ticizer loss. The material becomes stiffer, which leads to 3. 2. Contact Angle and Wettability The surface wettability of the membranes was eval- uated by measuring the contact angles of sessile droplets. As can be seen from Table 2, the contact angles of new 499Acta Chim. Slov. 2021, 68, 494–504 Kravanja et al.: Degradation of Plasticized Poly(1-chloroethylene) ... Table 4: Time-dependent contact angles of water droplets on naturally aged and damaged plasticized PVC membranes (location 2). CA 54.1°±1.5° 18.5°±3.5° / / t (s) 10 s 30 s 120 s 180 s Table 5: Time-dependent contact angles of water droplets on naturally aged and damaged plasticized PVC membranes (location 3). CA 52.1°±4.5° / / / t (s) 10 s 30 s 120 s 180 s Figure 4. Microstructure of new membranes’ upper layer (a, c) and lower layer (b, d). 500 Acta Chim. Slov. 2021, 68, 494–504 Kravanja et al.: Degradation of Plasticized Poly(1-chloroethylene) ... contractions and the prevalence of voids (Figure 5). It is assumed that the rearrangement and aggregation of mo- lecular chains are the main mechanisms of membrane degradation.19 Pedrosa et al.20 presented an interesting study using X-ray spectroscopy and SEM analysis of mem- branes exposed to different weathering conditions. They reported that aged membranes show numerous cracks and fractures and there is a significant decrease in chlorine content. Therefore, they suggested that dehydrochlorina- tion may be the main mechanism of deterioration. 3. 3. 2. Thickness Evaluation Cross-sectional microphotographs with thickness evaluations of the investigated plasticized PVC mem- branes are presented in Figure 6 and Table 6. It can be seen that the thickness of the aged membranes is decreased. As can be seen in Figure 6, there is also a visible difference in cross-sectional area between new and aged membranes. For example, the average thickness values for location 3 decrease from 1.18 mm to 1.09 mm. Changes in material thickness might be because of the reduction of plasticiz- er content. To justify plasticizer loss in material, chemical changes were identified and quantified using ATR/FTIR analysis. Figure 5. The microstructure of aged membranes extracted from different sampling locations: 1 (a, b), 2 (c, d), and 3 (e, f). The surface is more heterogeneous, with many craters, cracks, agglomerates, and voids. Table 6. Thickness of the new and aged membranes. Samples Average value (mm) Standard deviation (%) Location 1 1.17 1.25 Location 2 1.11 1.63 Location 3 1.09 1.63 New 1.18 2.05 Figure 6. Microphotographs in cross section with thickness evalua- tion for new membrane (a) and aged membranes (a, b, c). 501Acta Chim. Slov. 2021, 68, 494–504 Kravanja et al.: Degradation of Plasticized Poly(1-chloroethylene) ... 3. 4. ATR/FTIR Analysis FTIR spectra were recorded to investigate the chem- ical changes in the aged membranes from location 3 (with the highest exposed to solar radiation, near-ultraviolet radiation, atmospheric oxidation and moisture. Both the front (directly exposed to weathering) and side (inverted next to the insulation material) surfaces of the membranes were examined (Table 7, Figure 7 and 8). In FTIR, the spec- tra appearance of several characteristic bands can be seen. In particular, the C=O stretching vibration of the ester function from plasticizer is detected at 1720.50 cm–1. O-H bending is detected at 1425.40 cm–1 and symmetric and an- tisymmetric vibrations of the ester C-O-C group in the re- gion 1072.42 – 1280.08 cm–1. At the front side of aged mem- brane new peaks appear at 1660.71–1618.28 cm–1 that are associated with the stretching of the C=C bonds of the aro- matic ring, indicating that chemical degradation appeared in the membrane molecules 21. Compared to the front side of new membranes, the characteristic C-Cl stretching vi- bration at 642.95–605.65 cm–1 is not visible. This suggests that UV aging could have caused a dehydrochlorination reaction. These data are consistent with changes in the membrane morphology and elongation properties. On the back side of the membranes there is no visible difference in spectra between new and aged samples. The C-H stretch- ing mode can be observed at 2954.95–2852.72 cm−1 and the trans C-H wagging mode at 873.75 cm−1 22. Table 7: Main FTIR bands for the front and back sides of plasticized PVC membranes. Wavenumber, cm–1 Chemical Group Front side (new) 2954.95–2854.65 C-H stretching 1720.50 C=O stretching vibration 1425.40–1379.10 O-H bending 1280.08 C-O stretching 1122.57–1039.63 C-O stretching 873.75 C-H bending 740.67–605.65 C-Cl stretching Front side (aged) 2926.01 C-H stretching 1660.71–1618.28 C=C stretching 1253.73 C-O stretching Back side 2954.95–2852.72 C-H stretching (new and aged) 1720.50 C=O stretching vibration 1425.40 O-H bending 1122.57 C-O stretching 742.95–605.65 C-Cl stretching 3.5 Low-temperature Flexibility Three 50 mm wide rectangular samples from each sampling location were folded between two metal plates and then stored in a chamber to allow them to cool to the desired test temperature. In the first experiment, all sam- ples were subjected for 12 h to the temperature of 248 K (−25 °C). New samples meet the requirement according to the standard SIST EN 495-5 and stay unaltered after 180° bending around a small radius. In contrast, the flexibili- ty of all aged membranes decreased significantly. Visible cracks were observed on the surface of the membranes and it was also possible to see into the polyester reinforcement in the upper layer of the membrane. In the second experiment, the lowest temperature at which aged samples stay visually unaltered (without crack- ing) was recorded (Figure 9 a). The reproducibility of the test method was ± 5 K. There is a clear difference in low temperature flexibility between new and aged membranes. As can be seen in Figure 9, aged membranes are resistant to low temperature bending up to 278 ± 5 K, while new ones are resistant to 238 K. The results are in accordance with those in a study by Beer et al., who performed sim- ilar tests on PVC membranes after long-term exposure.9 Although flexibility is mainly an issue during installation and roof maintenance, the obtained results are important to understand the long-term behaviour of membranes. Figure 7. FTIR spectra at the front side of the new plasticized mem- branes (black line) and aged membranes (red line) operating in at- tenuated total reflection (ATR) mode. Figure 8. FTIR spectra at the back side of the plasticized mem- branes (black line) and aged membranes (red line) operating in at- tenuated total reflection (ATR) mode. 502 Acta Chim. Slov. 2021, 68, 494–504 Kravanja et al.: Degradation of Plasticized Poly(1-chloroethylene) ... 3. 6. TGA-DSC Analysis Figure 10 shows the thermal properties of a new membrane and an aged membrane (from location 3) heat- ed in nitrogen at a temperature range from 298 K up to 1273 K. The TG characteristic temperatures of the mem- branes are illustrated in Figure 10, including the onset temperature (Tonset), 5% weight loss temperature (T5%), the temperature at the maximum degradation rate (Tmax), and the maximum degradation rate (Rmax). It can be ob- served that new membranes have relatively high thermal stability below 470.93 K. In the case of aged membranes, the weathering effects led to a decrease in the Tonset val- ue from 470.93 K to 411.83 K, and for T5% from 560.65 K to 536.38 K. This seems to confirm that weathering aging over a long period of time resulted in degradation of the membrane molecules, as suggested by FTIR analysis. The initial negative heat flux shows that the de- composition reactions occur due to the heating of PVC, plasticizers and polyester mesh. In this step, dehydrochlo- rination takes place, producing HCl molecules.23 In the temperature range from 540 K to 650K, both membranes show a characteristic endothermic deviation from base- line, which is more evident in a new sample (Figure 10). The increase in heat flux at about 880 K could correspond to an exothermic transformation caused by crystallization of the samples. HCl is released from the melt and the mol- ecules are rearranged by cross-linking reactions. Above 1273 K, the total charring of the membranes corresponds to a high negative heat flux. 4. Conclusions The results of the measurements reaffirmed the sen- sitivity of plasticized PVC membranes reinforced with polyester mesh used for mechanically fixed unvented roof Figure 9. The lowest temperature at which aged samples stay visually unaltered (a). Cracks were observed along the upper layer of aged membranes after exposure to the temperature of 248 K (−25 °C) (b). Figure 10. Results of the TGA-DSC analysis for new and aged membranes from location 3. 503Acta Chim. Slov. 2021, 68, 494–504 Kravanja et al.: Degradation of Plasticized Poly(1-chloroethylene) ... systems over thermal insulation. During 10 years of use, plasticized PVC gradually degraded, and its primary phys- ical, chemical and mechanical properties changed. This tendency was observed in all three sampling locations. Therefore, the roofing area had to be completely replaced. The main conclusions are: • there is a tendency for tensile strength to increase with age. It appears that the polyester mesh is well encapsulated within the membrane matrix, • aged membrane samples exhibited shorter elonga- tion at break than new ones. This indicates a loss of flexibility under high humidity and thermal fluctu- ations, • wettability properties of examined membranes were highly affected by age, • the surface of aged membranes is more heterogene- ous that that of new ones, containing many craters, cracks, agglomerates, and voids. Similarly, the thick- ness of the aged membranes decreased probably due the migration of plasticizer content, • FTIR analysis confirmed the chemical changes in aged membranes. New peaks appear at 1660.71– 1618.28 cm–1, indicating that chemical degradation had occurred in the membrane molecules, • when low-temperature flexibility tests were per- formed, visible cracks were observed along the aged membranes, • thermal analysis revealed that the weathering aging effects resulted in reductions of Tonset and T5%. To reduce degradation and increase the durability of PVC membranes, new durable additives and plasticizers that are resistant to heat from solar radiation, near-ultravi- olet radiation, atmospheric oxidation and moisture should be used. In future studies, we will use time-temperature superposition models to assess the effect of aging on wa- terproofing membranes. Acknowledgments The authors would like to acknowledge the Sloveni- an Research Agency (ARRS) for partly financing this re- search within the frame of program P2-0046. Conflicts of Interest The authors declare no conflict of interest. 5. References 1. Y. Ma, S. Liao, Q. Li, Q. Guan, P. Jia and Y. Zhou, React Funct Polym. 2020, 147, 637–642. 2. Z. Kormosh, I. Hunka and Y. Bazel, Acta Chim. Slov. 2008, 55, 261–267. DOI:10.1002/jccs.200800052 3. M. Shamsipur, S. Sahari, M. Payehghadr and K. Alizadeh, Acta Chim. Slov. 2011, 58, 555– 562. 4. M. Zagorodnikova, V. Yartsev and V. Rupyshev, Adv. Mater. Technol. 2019, 2, 41–47. 5. M. Londschien and M. Bonnet, J. Appl. Polym. Sci. 2018, 135, 46689. DOI:10.1002/app.46689 6. P. Dunn, D. Oldfield and R. Stacewicz, J. Appl. Polym. Sci. 1970, 14, 2107–2116. DOI:10.1002/app.1970.070140818 7. L. Audouin, B. Dalle, G. Metzger and J. Verdu, J. Appl. Polym. Sci. 1992, 45, 2091–2096. DOI:10.1002/app.1992.070451204 8. M. Ito and K. Nagai, Polym. Degrad. Stab. 2007, 92, 260–270. DOI:10.1016/j.polymdegradstab.2006.11.003 9. H. Beer, A. Delgado, R. Paroli and S. Graveline: 10DBMC International Conference On 10. Durability of Building Ma- terials and Components LYON, International AG, Industri- estrasse, Lyon, France 2005, 1–7. 10. M. Blanco, N. Touze-Foltz, M. Pérez Sánchez, M. Redón-San- tafé, F.-J. Sánchez Romero, J. B. Torregrosa Soler and F. A. Zapata Raboso, Geosynth. Int. 2018, 25, 85–97. DOI:10.1680/jgein.17.00035 11. A. Kositchaiyong, V. Rosarpitak, H. Hamada and N. Sombat- sompop, Int. Biodeterior. Biodegradation 2014, 91, 128–137. DOI:10.1016/j.ibiod.2014.01.022 12. M. Gonçalves, J. D. Silvestre, J. de Brito and R. Gomes, J. Build. Eng. 2019, 24, 100710. DOI:10.1016/j.jobe.2019.02.002 13 R. Paolini, M. Zinzi, T. Poli, E. Carnielo and A. G. Mainini, Energy Build. 2014, 84, 1 333–343. DOI:10.1016/j.enbuild.2014.08.008 14. A. Ivanič, G. Kravanja, W. Kidess, R. Rudolf and S. Lubej, Ma- terials, 2020, 13, 2392. DOI:10.3390/ma13102392 15. Flagon, https://pdf.archiexpo.com/pdf/soprema/flagon/3193 -66009.html. 16. E. Huang, A. Skoufis, T. Denning, J. Qi, R. R. Dagastine, R. F. Tabor and J. D. Berry. J. Open Source Softw. 2021, 58, 2604 17. M. Lenartowicz, B. Swinarew, A. Swinarew and G. Rymarz, Int. J. Polym. Anal. Charact. 2014, 19, 611–624. DOI:10.1080/1023666X.2014.933071 18. A. Behboudi, Y. Jafarzadeh and R. Yegani, Chem. Eng. Res. Des. 2016, 114, 96–107. DOI:10.1016/j.cherd.2016.07.027 19. Y. Fu and J. R. Lakowicz, Nature, 2011, 472, 178–179. DOI:10.1038/472178a 20. A. Pedrosa and M. Del Río, Materiales de Construcción 2017, 67, 109. DOI:10.3989/mc.2017.08915 21. A. Royaux, I. Fabre-Francke, N. Balcar, G. Barabant, C. Bol- lard, B. Lavédrine and S. Cantin, Polym. Degrad. Stab. 2017, 137, 109–121. DOI:10.1016/j.polymdegradstab.2017.01.011 22. S. Ramesh, K. H. Leen, K. Kumutha and A. K. Arof, Spectro- chim. Acta A Mol. Biomol. Spectrosc. 2007, 66, 1237–1242. 23. A. Marongiu, T. Faravelli, G. Bozzano, M. Dente and E. Ran- zi, J Anal Appl Pyrolysis. 2003, 70, 519–553. DOI:10.1016/S0165-2370(03)00024-X 504 Acta Chim. Slov. 2021, 68, 494–504 Kravanja et al.: Degradation of Plasticized Poly(1-chloroethylene) ... Except when otherwise noted, articles in this journal are published under the terms and conditions of the  Creative Commons Attribution 4.0 International License Povzetek Z namenom ugotoviti vzroke degradacije in preučitve vplivov naravnega staranja na obstojnost plastificiranih polivi- nilkloridih membran, smo izvedli vzorčenje poškodovanih membran iz industrijskih strešnih kritin in jih primerjali z novimi. Določili smo natezne trdnosti, stopnjo elongacije do pretrga, in omočljivost membran. Nato smo z uporabo ske- nirane elektronske mikroskopije (SEM) analizirali morfološke mikrostrukturne spremembe in določili debeline mem- bran. Za preučevanje kemijskih sprememb v starih membranah smo uporabili Fourierevo analizo z infrardečo spektro- skopijo (FTIR). Z namenom preučevanja toplotne razgradnje smo uporabili termogravimetrično analizo in diferenčno dinamično kalorimetrijo (TGA-DSC). Rezultati nakazujejo na očitne spremembe mehanskih, fizikalnih in kemijskih lastnosti poškodovanih membran, kar nakazuje na zmanjšanje vsebnosti plastifikatorja. Površina membran postane trša, kar povzroči krčenje in razširjenost praznin. Povprečne debeline membran na preseku se zmanjšajo. Zaradi degradacije hidroizolacije iz plastificiranega PVC-ja, je bilo strešno kritino potrebno zamenjati v celoti.