Study of high-density polyethylene recycling

Potreba po plastičnih izdelkih je vsako leto večja, saj imajo v primerjavi s tradicionalnimi materiali ugodne lastnosti. Zaradi velike količine uporabljenih plastičnih izdelkov pa se ustvari tudi veliko odpadkov, ki jih moramo za trajnostni razvoj zmanjšati, to pa lahko storimo s ponovno uporabo in recikliranjem. Glavni namen te zaključne naloge je ugotoviti, kako recikliranje vpliva na lastnosti polietilena visoke gostote (HDPE). Predstavili smo nekatere značilnosti HDPE ter oblike razpada polimerov. Glavni vplivi za degradacijo so termo-mehanske obremenitve med življenjsko dobo izdelka in med recikliranjem. Povzeli smo študijo do 100x recikliranega polietilena visoke gostote in dodatne raziskave, kjer so temu materialu dodajali enak surov material. Ugotovili smo, da se nekatere lastnosti poslabšajo šele po 10 recikliranjih. Pregledali smo tudi druge študije, ki so proučevale vpliv dodajanja drugih materialov, kot je polietilen tereftalat, ki ugodno vpliva na mehanske lastnosti, če dodamo tudi 5% aditiva za kompatibilnost.The need for plastic is increasing every year because of its favourable properties. Producing more plastic products, however, generates waste which we must manage by reusing and recycling. The main focus of my thesis is to study how recycling effects the properties of high-density polyethylene (HDPE) after recycling. We presented a few basic properties of HDPE and the main degradation mechanisms. The primary reason for degradation is thermo-mechanical stress during the lifetime of a product as well as recycling process. In a study of extensively recycled HDPE (up to 100x) we found out that some mechanical properties do not deteriorate for the first 10 cycles. We also analysed some other studies, which showed the influence of the addition of PET is positive for some mechanical properties if we also add a compatibilising additive