Correlation between morphology and mechanical properties in low density polyethylene/ethylene vinyl acetate copolymer blends

In this study the relationship between microstructure and mechanical properties of LDPE / EVA blends was investigated. For this purpose four blends with different compositions consist of (70/30), (60/40), (50/50) and (40/60) of LDPE/EVA were prepared by melt mixing within a twin screw extruder. The results revealed that the mechanical behavior of the blends converts from tough plastic to rubbery behavior by increasaing EVA content. The yield stress values of the blends decreased by increasing EVA content and the yield point finally was disappeared in the (50/50) composition, which indicates a rubbery like behavior of LDPE/EVA blends with the compositions of (50/50) and (40/60). The phase inversion composition occurred at (50/50), where a clear interconnected co-continuouse morphology was observed. Once co-continuouse morphology was obtained, the further increment of EVA content in the blend composition leads to significant drop of hardness in the EVA-rich blend (40/60) with droplet-matrix morphology.