The temperature dependence of the irradiation cross-linking of polyethylene

The dependence of the cross-linking of polyethylene upon the temperature during and after irradiation was measured as gel-dose data. The gel fraction increased not only with irradiation temperature, but also with the storage temperature after irradiation. High density polyethylene was more dependent on temperature than low density polyethylene. The allyl type radical after irradiation in cross-linked polyethylene was found to have longer lifetime than that in non-cross-linked polyethylene. It was also found that temperature dependence was not interpreted only by the free radical living in the polyethylene. It was attempted to elucidate the mechanism of the temperature dependence of cross-linking. (author)