Some properties of silane-grafted moisture-crosslinked polyethylene

Silane‐grafted polyethylene materials are processed in conventional thermoplastic fabrication machines. The shaped articles are then crosslinked in water by the formation of Si‐O‐Si crosslinks. This paper represents studies on the crosslinking progress in different environments at various temperatures. Molecular orientation is shown to become permanent and mostly irrecoverable even at 150°C, in the silane‐grafted solid state crosslinked specimens (the crosslinking temperature in water is well below the polymer melting temperature). These frozen molecular orientations have a significant effect on the tensile properties of the crosslinked materials causing higher yield stresses and lower elongations at break. The thermal and tensile properties of some silane‐grafted crosslinked polyethylene samples and peroxide‐crosslinked materials are compared and analyzed.