Gluing of wood using waste polyethylene

Uporaba plastičnih izdelkov je vse bolj popularna, zaradi česar se tudi odpadna plastika po svetu vse bolj kopiči. Odpadno plastiko lahko recikliramo ali ponovno uporabimo, najpomembneje pa je, da preprečimo nesmiselno uporabo le-te. Vse bolj pomemben je koncept 5R, ki temelji na petih korakih: preprečevanje, ponovna uporaba, recikliranje, predelava in odstranjevanje. V naši raziskavi smo les lepili z odpadnimi vrečkami iz polietilena. Po standardu SIST EN 205:2016 smo nato ugotavljali strižno trdnost lepilnih spojev. Zanimal nas je vpliv temperature lepljenja in ohlajanja na lepilni spoj. V prvem delu raziskave smo bukove lamele lepili pri temperaturi 175 °C in 150 °C ter jih ohlajali bodisi v stiskalnici na 25 °C ali pa jih takoj vzeli iz stiskalnice po lepljenju pri 175 °C in 150 °C. V drugem delu raziskave smo ugotavljali vpliv števila slojev plastičnih vrečk na strižno trdnost lepilnega spoja. Testirali smo strižno trdnost pri enem, dveh in treh slojih. Ugotovili smo, da je ohlajanje lepilnega spoja po lepljenju pri 150 °C pozitivno vplivalo na končno trdnost, medtem ko je bil pri 175 °C vpliv negativen. Najvišjo povprečno strižno trdnost, 6,3 N/mm2, smo ugotovili pri ohlajenih preizkušancih, lepljenih pri 150 °C. Ugotovili smo tudi, da večje število slojev pozitivno vpliva na strižno trdnost lepilnega spoja. Pri treh slojih iz polietilenskih vrečk je bila strižna trdnost najvišja, najnižja pa je bila pri enem sloju.The use of plastics is increasing in popularity, which is why the plastic waste is also increasing. While waste plastics can be recycled or reused, the most important thing is to reduce the use of plastic in the first place. The 5R concept of reduce, reuse, recycle, recover and reject is gaining popularity. We researched the gluing of wood using waste polyethylene. All shear strength tests on test subjects were made according to the standard SIST EN 205:2016. We were interested in how the temperature affects the test subjects. The first part of the research consisted of tests, where we glued beech test subjects at the temperature of 150 °C and 175 °C. Half of the test subjects were left to cool in the press to 25 °C, the other half were taken out of the press immediately after pressing. In the second part of the research, we determined the influence of the number of layers of plastic bags on the shear strength of the adhesive joint. We tested the shear strength of one, two and three layers. Cooling of the adhesive joint at 150 °C brought positive results, whereas the cooling brought negative effects at 175 °C. The highest average shear strength was 6,3 N/mm2 . The number of layers of plastic bags affects the shear strength with more layers also increasing the shear strength of the joint