Abstract
Gel fraction and physical properties of polymers were measured after irradiation at various conditions for investigating the effect of temperature and atmosphere on the radiation induced cross-linkig and scission of polymers. The results were summarized as follows. The heating improved the efficiency of cross-linkig of high density polyethylene during irradiation. The rate of cross-linkig irradiated at 80 °C was found out to be second times of that of irradiated at 4 °C. Low density polyethylene and ethylene-vinyl acetate copolymer were irradiated by electron beam in nitrogen, air and oxygen. The measurement of gel fraction showed that the decrease in the cross-linking efficiency was in that order. The dose rate effect on the cross-linking efficiency was not observed when irradiation was performed under the dose rate ranging from 6 kGy/s to 600 kGy/s. The irradiation decreases the melt viscosity of polytetrafluoroethylene and electron beam had higher efficiency than γ ray.
