Influence of temperature on radiation-induced graft polymerization of styrene onto poly(ethylene terephthalate) nuclear membranes and films

Abstract

The effect of temperature on the kinetics of radiation-induced graft polymerization of styrene onto poly(ethylene terephthalate) (PETP) nuclear membranes with varying parameters (pore diameter, pore density and average distance between the pores) and onto PETP films of different thickness has been studied. Graft polymerization was carried out by preirradiation in air and in vacuum. The overall activation energy of grafting and the activation energy of swelling of PETP in toluene have been obtained. It was found that for preirradiation in vacuum, an Arrhenius plot has two linear ranges for the initial grafting rate. The activation energy in the low temperature range correlates with the activation energy for PETP swelling. The activation energy in the high temperature range is determined by the kinetics of graft polymerization. For preirradiation in air, the Arrhenius plot of the initial grafting rate gives an activation energy which approximately corresponds to the initiation of grafting by oxy radicals. The dependence of the critical thickness of the PETP matrix on temperature has also been obtained for preirradiation in vacuum. The form of this dependence is identical to that of the rate of graft polymerization.