Properties of three types of crosslinked polyethylene

The same base resin, a HDPE with vinyl–silane units grafted along the backbone, was subjected to three different types of crosslinking: (a) using peroxides and heat, (b) using a catalyst under high humidity, and (c) using high‐energy radiation. Macroscopic properties, such as tensile behavior‐at‐break, shear modulus, gel content, and crystallinity were measured for all three types of crosslinked material. Although the mechanical and rheological properties appear to indicate differences in distribution of crosslinks, the major differences are seen for the degree of crystallinity. These differences are rationalized on the basis of the mechanism of crosslinking and the resultant location of crosslink sites.