Estimation of Chain Fracture during the Cross-linking of Rubber Hydrocarbons by High-Energy Radiation

Abstract

EXPOSURE of hydrocarbon polymer molecules to high-energy radiation results either in a decrease in their molecular weight or intermolecular interaction, with the eventual formation of an insoluble network. The primary factor which determines what happens is the relative incidence of fracture of the main chain of carbon atoms to cross-link formation. The ratio of fractures to cross-links, β, has usually been estimated from studies of the solubility of irradiated polymers. The bulk of such work has been on polyethylenes, and even under comparable experimental conditions widely differing estimates of β have been reported. Measurements of the stress relaxation during irradiation have also been used in an attempt to obtain alternative estimates of the chain fracture during irradiation¹.