The mechanism of radiation damage to elastomers. II. Crosslinking and antirad action

Abstract

Abstract The effect of antirads (compounds added to reduce changes of polymer properties during irradiation) on the crosslink yields in black‐loaded natural rubber stocks during gamma irradiation has been measured. The crosslink yields were determined by swelling techniques. Antirads decrease the crosslink yields if oxygen is absent. Oxygen alone effectively decreases crosslink yields. In the presence of oxygen some antirads further decrease crosslink yields, while others increase crosslink yields by their presence. These results may be explained in terms of competitive reactions between R. radicals, the antirad, and oxygen. Evaluation of the ratios of crosslink yields and scission yields indicate that most of the scission is temporary in nature, the chain breaks being reformed rapidly.