Compatibilization of PET-PE blends for the recycling of multilayer packaging foils

The compatibilization of a virgin polyethylene terephthalate/polyethylene (PET/PE) blend and a recycled multilayered post-industrial food tray of similar composition are investigated. The compatibilizers of focus are a propylene ethylene rubber (PER) and a styrene ethylene / butylene styrene triblock copolymer grafted with maleic anhydride (SEBS-g-MA). This work examines the effect of these compatibilizers on both the mechanical properties (impact and tensile properties) and morphology of the virgin blends and verifies whether these effects are transferable to an actual waste stream of post-industrial food trays with comparable composition. Regarding the virgin blends, it was concluded that both compatibilizers increase the impact strength and elongation at break of the material, wherein PER increases the impact strength more effectively than SEBS-g-MA. Moreover, PER succeeds in maintaining both tensile strength and stiffness of the blends. Also, the morphology of the PER blends shows clear indication of rubber toughening. The results of the virgin blends are to a certain extent transferable to an actual waste stream consisting of post-industrial food trays with comparable composition. PER shows to be the most promising candidate for increasing toughness while maintaining stiffness and tensile strength.