molecular and morphological studies to understand the strain hardening behavior of uhmwpe/hdpe blends

The most common route to improve the properties of bimodal high-density polyethylene (bi-hdpe) pipes is to add the controlled-amounts of high molecular weight (hmw) chains, without compromising the melt flowability. to elucidate the influence of hmw chains on slow crack growth (scg), blends of bi-hdpe and ultra-high molecular weight polyethylene (uhmwpe) at different contents (1, 5 and 10 wt.%.) were examined through strain hardening (sh) test. meanwhile, the correlation between sh modulus (), entanglement density and crystallization behavior have been investigated thorough rheological and thermal analysis. addition of uhmwpe up to 10 wt.%, augmented the value of bi-hdpe from 44 to 56 mpa. this is attributed to the higher amounts of inter-cluster links of uhmwpe and the ability of co-crystallization between components. the detailed examination of the longitudinal morphology of strain-hardened samples revealed an alternating banded structure of etched defects. when uhmwpe content is beyond 1 wt.%, the defect size and bands thickness become considerably smaller, indicating a more oriented structure.