Properties of SBR/NR Blend: The Effects of Carbon Black/Silica (CB/SiO2) Hybrid Filler and Silane Coupling Agent

In the current research, investigation of natural rubber (NR)/styrene butadiene rubber (SBR) blend reinforced with carbon black (CB)/silica (SiO2) and with and without silane coupling agent (SCA) was analyzed. The total hybrid filler (CB/SiO2) concentration in the composite was fixed at 50 phr. Cure characteristics, mechanical properties and surface morphology were examined. The results revealed that as the SiO2 content increase, the optimum cure time, scorch time, minimum torque, and maximum torque of NR/SBR-CB/SiO2 composites with and without SCA increased. Except for maximum torque, the optimal cure time and minimum torque of NR/SBR-CB/SiO2 composites with SCA were lower than those without SCA. Compared with NR/SBR composites with SCA, addition of 0/50 CB/SiO2 resulted in 53% decrease of tensile strength and 81% increase of elongation at break, superior to that of NR/SBR composites without SCA. The results revealed that as the SiO2 content increase, the optimum cure time, scorch time, minimal torque, and maximum torque of NR/SBR-CB/SiO2 composites with and without SCA increased. Except for maximum torque, the optimal cure time and minimum torque of NR/SBR-CB/SiO2 composites with SCA were lower than those without SCA.