34 KB74 KB26 KB200020262011Čuk, NatašaKunaver, MatjažMedved, Sergejštevilka:3letnik:45str. 241-245ISSN:1580-2949COBISSID:859818URN:URN:NBN:SI:doc-SMJSZSF7enInštitut za kovinske materiale in tehnologijeMateriali in tehnologijeiverne ploščemehanske lastnostimelaminske smoleutekočinjen lesProperties of particleboards made by using an adhesive with added liquefied wood| Lastnosti ivernih plošč, izdelanih z uporabo lepila z dodanim utekočinjenim lesom|In this study, three-layer particleboards were produced using liquefied wood in an adhesive mixture. The influence of two different formaldehyde resins: melamine-formaldehyde and melamine-urea-formaldehyde resin and two various catalysts: ammonium sulfate and ammonium formate on the particleboard properties was investigated. There were also two pressing parameters examined: temperature and time. The following physical and mechanical properties of particleboards were measured: board thickness, density, moisture content, bending strength and modulus of elasticity, internal bonding strength, surface soundness, thickness swelling and formaldehyde content. The results showed that properties of produced particle boards were better when melamine-formaldehyde resin and ammonium formate as a catalyst were used in combination with liquefied wood in the adhesive mixture. Also, mechanical properties were improved as the press time and press temperature increased. The optimal mechanical properties of particleboards made with the utilization of the liquefied wood in the adhesive mixture were achieved at 3 min press time and 180 °C press temperature using melamine-formaldehyde resin and 3 % of ammonium formate as a catalyst. A very important characteristic is the low formaldehyde content and that is extremely important in the provision of better quality of life. With the liquefaction of wood and the application of liquefied wood in the particleboard production wood biomass exploitation could be significantly increased. We are able to produce new materials from renewable resources that can be a great alternative to the raw materials, originating from crude oilIzdelali smo trislojne iverne plošče, kjer smo za pripravo lepila uporabili utekočinjen les. Ugotavljali smo, kako v kombinaciji z utekočinjenim lesom na lastnosti ivernih plošč vplivata dve različni formaldehidni smoli: melamin-formaldehidna in melamin-urea-formaldehidna smola, ter dva različna katalizatorja: amonijev sulfat in amonijev formiat. Ugotavljali smo tudi vpliv dveh parametrov stiskanja, in sicer temperature stiskanja in časa stiskanja. Fizikalne in mehanske lastnosti, ki smo jih ivernim ploščam določili, so bile: debelina plošče, gostota, vsebnost vlage, upogibna trdnost in modul elastičnosti, razslojna trdnost, čvrstost površine, debelinski nabrek in vsebnost prostega formaldehida. Rezultati so pokazali, da smo izboljšali lastnosti ivernih plošč, ko smo v kombinaciji z utekočinjenim lesom uporabili melamin-formaldehidno smolo in amonijev formiat kot katalizator. Ugotovili smo tudi, da so se lastnosti izdelanih ivernih plošč s časom in temperaturo stiskanja izboljšale. Optimalne lastnosti ivernih plošč, pri katerih smo lepilni mešanici dodali utekočinjen les, smo dosegli pri času stiskanja 3 min in temperaturi stiskanja 180 °C, pri uporabi melamin-formaldehidne smole in 3 % amonijevega formiata kot katalizatorja. Zelo pomembna pri izdelanih ivernih ploščah je tudi majhna vsebnost prostega formaldehida, kar močno vpliva na izboljšanje kvalitete bivanja. Z utekočinjanjem lesa in njegovo uporabo pri izdelavi ivernih plošč povečamo izrabo lesne biomase. Iz obnovljivih virov tako lahko sintetiziramo nove materiale, ki so odlična alternativa materialom, ki jih sicer pridobivamo iz surove nafteTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije