In situ silica reinforcement of vinyltriethoxysilane-grafted styrene-butadiene rubber by sol-gel process

Grafting polymerization of vinyltriethoxysilane (VTES) onto styrene-butadiene rubber (SBR) was firstly carried out in latex, using potassium persulfate (KPS) as initiator. The grafted SBR was further reinforced with silica produced by sol-gel reaction of tetraethoxysilane (TEOS). The grafted of VTES onto SBR was characterized and confirmed by ATR-FTIR and ¹H-NMR. Results revealed that the addition of VTES could considerably improve the content of silica, bound rubber in SBR and utilized efficiency of TEOS. Meanwhile, the curing characteristics and mechanical properties of the vulcanized in situ reinforced SBR-g-VTES were also investigated and compared with that of the silica-reinforced SBR prepared by mechanical mixing. The delta torque, tensile, and tear strength of in situ reinforced SBR-g-VTES were higher than that of silica-reinforced SBR. Dynamic mechanical analysis showed that the interaction between silica and SBR of in situ reinforced SBR-g-VTES was also better than that of the silica-reinforced SBR.