Effect of thermal aging on crystallization behavior and mechanical properties of LDPE/POE blends

The effect of thermal aging on the properties of low density polyethylene(LDPE)/polyolefin elastomer(POE) blends was studied in air oven at 70°C for 8 weeks. Influence of thermal aging on blend crystallization behavior was characterized by differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD). Withal the effect of thermal aging on the mechanical properties was also investigated. The blend with w(POE) of 30% had excellent thermal aging resistance, its elongation at break increased at the early stage and decreased slightly in the late period; however its tensile strength kept almost changeless. The thermal aging had remarkable influences on the crystallization of the blends in the early stage. During the thermal aging, imperfect crystallization which formed during the preparation of LDPE/POE blends re-crystallized resulting in bigger crystals. As a result, the homogeneity of LDPE crystallization became better.