Silica reinforced epoxidized solution-polymerized styrene butadiene rubber and epoxidized polybutadiene rubber nanocomposite as green tire tread

Solution-polymerized styrene butadiene rubber (SSBR) and high cis-polybutadiene rubber (BR) are usually used as matrix and silane coupling agent (SCA) modified silica as the filler in the conventional green tire tread. However, the SCA cannot achieve uniform distribution of silica, moreover the modification process generates volatile organic compounds. In this work, a novel silica reinforced epoxidized SSBR(ESSBR)/epoxidized BR (EBR) nanocomposite (S-ESSBR/EBR) without SCA is prepared. The ESSBR and EBR with different epoxidation degree are synthesized by an oxidant H₂O₂ and reaction-controlled phase-transfer catalyst CPC-PW₄O₁₆. The microstructure and performance of S-ESSBR/EBR nanocomposites are investigated and compared with the silica reinforced SSBR/BR nanocomposite (S-SSBR/BR-Si75) using Si75 as SCA. Silica nanoparticles transfer from ESSBR phase to EBR phase with increasing epoxidation degree of EBR, so the distribution of silica in two phases becomes homogeneous. The S-ESSBR/EBR nanocomposite exhibits high wet skid resistance, low rolling resistance and excellent abrasion resistance as green tire tread.