Effect of catalyst on in situ silica reinforcement of styrene-butadiene rubber vulcanizate by the sol-gel reaction of tetraethoxysilane

In situ silica reinforcement of styrene-butadiene rubber (SBR) vulcanizate has been achieved by the sol-gel reaction of tetraethoxysilane (TEOS) using n-butylamine as a catalyst. SBR was vulcanized with sulfur and soaked in TEOS and in an aqueous solution of the catalyst. When hydrochloric acid was used as a catalyst for the sol-gel reaction, silica particles were not introduced into the SBR matrix in this study. The increase of the dynamic modulus and tensile strength at break was considered to be due to the interaction between the rubber and the in situ silica filler in the SBR vulcanizate.