Temperature effects on radiation induced phenomena in polymers

Temperature dependence of radiation induced effect on polytetrafluoroethylene and polystyrene was examined. Polytetrafluoroethylene is crosslinked just above the melting temperature. Effective chain scission takes place at relative high temperatures below the melting point. However, less chain scission occurs at a cryogenic temperature 77 K. Polystyrene is crosslinked effectively at room temperature, while it is degraded at high temperatures above the glass transition temperature. Significant differences in their radiation effect between atactic and syndiotactic structures, as well as between amorphous and crystalline states were observed. (author)