Thermo-mechanical recycling effects on morphology and properties of ethylene vinyl acetate copolymer/olive husk flour composites

Abstract

The effects of thermo-mechanical recycling through repeated extrusion cycles on morphology and properties of neat ethylene vinyl acetate copolymer (EVA) and EVA/olive husk flour (OHF) composites (70/30 w/w) with and without ethylene–butyl acrylate–glycidyl methacrylate (EBAGMA) compatibilizer were investigated in a single screw extruder machine up to five repeated cycles. The study showed that no significant modifications in the properties of the virgin EVA/OHF composite were observed along the recycling and this stability was further enhanced in the presence of EBAGMA. Indeed after five repeated extrusion cycles, the chemical structure and properties of both uncompatibilized and compatibilized composites remained unchanged compared to the neat polymer, which was subjected likely to cross-linking, in the fifth cycle. Furthermore, SEM analysis showed a better dispersion of OHF particles in EVA matrix and a good filler–polymer interfacial adhesion, being, however, more pronounced for the compatibilized composite.