Different compatibility approaches to improve the thermal and mechanical properties of EVA/starch composites

Biocompostable composites based of ethylene‐co‐vinyl acetate (EVA) copolymer were prepared by using a twin‐screw extruder. The compatibility between EVA/starch composites were improved either by addition of polyethylene‐grafted maleic anhydride (PE‐g‐MA), or by reactive extrusion with maleic anhydride (MA) and benzoyl peroxide. The crystallinity of the non‐compatibilized composites increased with the starch content. The addition of PE‐g‐MA increased the crystallinity of the composites made with up to 20 wt% of starch. The thermal stability of EVA/starch composites decreased with increasing the starch content, and the addition of PE‐g‐MA compatibilizer enhanced the thermal stability of the composite. The in‐situ grafting with MA and PBO led to an increase in the thermal stability of the composites containing higher amounts of starch. Further, the mechanical properties of the compatibilized EVA/starch composites were improved with increasing the starch content and this was ascribed to the improved interfacial interactions between starch and EVA. POLYM. COMPOS., 40:3242–3253, 2019. © 2019 Society of Plastics Engineers