Preparation of silica-reinforced styrene–butadiene rubber via co-coagulation process

Abstract

Styrene–butadiene rubber (SBR) was reinforced with silica (SiO2) by co-coagulating process. This study investigated the SiO2 amount, stirring time and pH value affecting the SiO2 content, curing characteristics and mechanical properties of SBR. Results showed that SiO2 content and reinforcing behavior were greatly influenced by the amount of SiO2 and pH value. The torque, tensile strength and elongation at break were optimal when the mass fraction of SiO2 was 21.5 wt%, stirring time was 6 h and pH value was 6.57. The utilized efficiency of SiO2 decreased with the increasing amount of SiO2 but increased with the increasing stirring time. The optimum cure time decreased with the increasing amount of SiO2. Both tensile strength and elongation at break decreased with the increasing pH value. Scanning electron microscopy observations showed that the SiO2 nanoparticles were distributed evenly in the SBR.