Reinforcement of Acrylonitrile—Butadiene Rubber by Silica Generated in situ

Abstract

Abstract In situ silica reinforcement was applied to the acrylonitrile—butadiene rubber (NBR) vulcanizates. The amount of in situ silica introduced in the NBR vulcanizates was limited due to the high polarity of NBR. The presence of γ-mercaptopropyltrimethoxysilane (γ-MPS) in the NBR vulcanizate increased the conversion of TEOS in the sol-gel reaction and resulted in the higher amount of in situ silica, compared to the system without γ-MPS. The obtained silica was very fine and dispersed very homogeneously. In situ sol-gel reaction of TEOS in the NBR vulcanizates mixed with a conventional silica (VN-3) was also carried out. The reinforcement efficiency in this system increased with the increase of the amount of mechanically mixed conventional silica. Interestingly, the hysteresis loss decreased by the in situ filling of silica.