Radiation cross-linking of different kinds of polyethylenes

Cross-linked low density and high density polyethylenes are commonly used in industrial applications such as high voltage insulation and hot water piping. Different methods for cross-linking polyethylenes include chemical cross-linking by using organic peroxide silane cross linking by grafting silane gropups on the polymer chain and radiation cross linking by using high energy electron beam or gamma-radiation. Radiation cross-linking constitutes one of the most convenient methods. The effect of radiation dose on the degree of cross-linking, crystallinity and mechanical properties has to be explored and understood for the use of cross-linked material in any application. This study compares the effect of radiation cross-linking and radiation dose on different types of polyethylene. Four different kinds of polyethylenes were studies including high density polyethylene (HDPE). Low density polyethylene (LDPE), linear low density polyethylene (LLDPE) an ultra-high molecular weight polyethylene (UHMWPE). These materials were irradiated using a high-energy electron beam at room temperature with radiation dose ranging form 0-60 mrad. The properties studied included the effect of radiation dose on cross-link density and crystallinity, and the mechanical behavior of some selected materials. (author)