Influence of Electron Beam Irradiation as One of the Mixed Crosslinking Systems on the Structure and Properties of Nitrile Rubber

Abstract

Abstract The influence of electron beam on the nitrile rubber vulcanizates at varying levels of sulfur is reported. A higher crosslinking density, reduced elongation at break, increased modulus and tensile strength have been observed for the irradiated rubbers, as compared to the control rubber vulcanizates. The vulcanizate containing higher amount of sulfur, tends to form more crosslinkages on impinging with electron beam. This behavior is explained by the formation of monosulphidic linkages and is ascertained with the help of IR analysis (ATR mode), solid-state NMR analysis and chemical probe treatments of the irradiated vulcanizates. The implausible nature of these mixed crosslinking systems with electron beam as an additional crosslinker is explained with a kinetic model using steady state principle. A mechanistic path is suggested for explaining the structural changes on irradiation of these vulcanizates, which is supported by this model.