ABSTRACT:The presence of a paraffin wax has been found to considerably reduce the radiation dose required to completely polymerize styrene, but no detectable grafting of styrene to wax occurs. The rate of polymerization was found to be greatly dependent on the styrene/wax composition, and the activation energy was determined to be -7.4 kcal/mole. The addition of scavengers indicates a free-radical mechanism which is confirmed by preirradiation experiments, showing the wax to be the main source of initiating radicals. The negative activation energy is explained by an induced gel-effect caused by the semirigid wax matrix, which further enhances the polymerization rate, which cannot be accounted for entirely in terms of increased radical production in the wax.