Preparation and properties on the composite of silica/emulsion polymerization styrene butadiene rubber grafted by silicane

Vinyltriethoxysilane (VTES) was grafted onto styrene butadiene rubber (SBR) via emulsion polymerization under two kinds of thermal initiators respectively. The structure of grafted SBR was characterized. The mechanism of emulsion grafting was investigated. The grafting ratio of SBR, grafting efficiency of VTES and properties of grafted SBR were investigated and compared with that of SBR grafted by methyl methacrylate(MMA) and styrene(St), respectively. The results indicate that the grafting efficiency of VTES is the highest of all, and the grafting reaction occurs by addition on C=C for potassium peroxydisulfate (KPS), while by removal of an allylic hydrogen atom from SBR and by addition on C=C at the same time for benzoyl peroxide (BPO). SBR grafted by VTES (SBR-g-VTES) using KPS as initiator can get good performance of grafted rubber. The results also show that the SBR-g-VTES prepared by these conditions is reinforced by silica, compared with the composite of SBR/SiO₂. The tensile strength of SBR-g-VTES/SiO₂ is higher. The scanning electron microscope (SEM) shows that the silica is well-distributed in SBR-g-VTES.