ABSTRACT
Radiation crosslinking of elastomers has been receiving increasing attention. The reactions induced by high-energy ionizing radiation are very complicated and the mechanisms still remain not entirely comprehended. Ionizing radiation crosslinking of acrylonitrile-butadiene rubber, filled with 40 phr of silica, with incorporated sulfur crosslinking system was the object of study. To investigate the influence of components such as sulfur and crosslinking accelerator-dibenzothiazole disulfide (DM) on the process, a set of rubber samples with various sulfur to crosslinking accelerator ratio was prepared and irradiated with 50, 122 and 198 kGy. Crosslink density and crosslink structure were analyzed and mechanical properties of the rubber samples were determined. Inhibiting effect of DM and sulfur on the radiation crosslinking process was found. The rubber vulcanizates having sulfur in composition characterized themselves with hybrid crosslinks-both carbon-carbon and sulfide, with varying degree of sulphidity, depending on the sulfur and DM content. The presence of sulfide crosslinks increased tensile strength of the rubber samples.
