Effects of ethylene‐octene copolymer and ethylene‐propylene copolymer on crystallization, morphology, and foaming properties of ethylene‐vinyl acetate copolymer

Abstract

Ethylene‐octene copolymer (EOC, three EOCs with different octene content used in this study) and propene‐ethylene copolymer (EPC, three EPCs with different ethylene content used in this study) can have effects on the crystallization dynamics, crystal structure, and foaming properties of ethylene‐vinyl acetate copolymer (EVA). For unfoamed EVA/EOC and unfoamed EVA/EPC blends, both EVA/EOC and EVA/EPC blends show phase separation structure. The foam cells in EVA/EOC blends have better uniformity compared to those in EVA/EPC blends, which result from the better compatibility of EVA and EOC than EVA and EPC obtained from the morphology analysis. For the blends with different crystallization ability of EOC or EPC, the blends with lower crystallinity has more uniform cell distribution than blends with higher crystallinity, due to the crystallization zone cause heterogeneous crosslinking and foaming of the blend. Both EOC and EPC can impart higher elasticity to EVA foamed materials. EOC was found to be more suitable for blending with EVA for foamed materials, offering the potential to obtain EVA/EOC foamed materials with excellent performance.Highlights Ethylene‐octene copolymer with higher octene content has better effect on foaming property of ethylene‐vinyl acetate copolymer than ethylene‐propylene copolymer. Ethylene‐propylene copolymer can decrease the foaming temperature of ethylene‐vinyl acetate copolymer. A mechanism of foaming for ethylene‐vinyl acetate copolymer/semi‐crystallized polymer blends is proposed. Achieved in‐depth understanding of structure–property relationship about ethylene‐vinyl Acetate copolymer/polyolefin elastomer foamed material.