On the relationship between microhardness and crystal perfection of chain-extended polyethylene

The crystal hardness-crystal perfection correlation of polyethylene (PE) samples crystallized at high pressure from the melt (chain extended) has been studied and compared to melt crystallized samples at atmospheric pressure (chain folded). For this purpose the chain extended PE samples were analyzed by WAXS and the paracrystalline lattice distortion parameter values, g(110), were calculated. Results are discussed in the light of structural and thermodynamical predictions.. Analysis of data confirm the close existing correlation, previously found for chain-folded crystals, between the crystal hardness and g(110), including now both the values for chain-folded and chain-extended crystals.