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.