Radiation effects on polymers—V: Vulcanization of styrene-butadiene rubber (SBR) with gamma radiation and coagents

Possible enhancement of the radiation-induced vulcanization of SBR by polyfunctional allyl and vinyl monomers, was tested. Polyfunctional allyl esters did not enhance the radiation vulcanization; in fact they retarded the process and so can be considered as “antirads”. Di- and tri-vinyl monomers acted individually as effective radiation coagents. In their presence, the dose required for satisfactory curing was 7–10 MR instead of 40 MR in the case of unenhanced vulcanization. The results indicate that vinyl esters are more effective coagents than vinyl amides. The physico-mechanical properties of vulcanizates, obtained in the presence of 10–30 parts of vinyl coagents per 100 parts of SBR. are of the same level as those obtained by conventional sulphur vulcanization.