A combined experimental and molecular dynamics simulation study on the structures and properties of three types of styrene butadiene rubber

The styrene/butadiene ratio of styrene butadiene rubber (SBR) greatly affects the inherent characteristics and material performance of the rubber. In this study, SBR vulcanizates comprising the same amount of carbon black and other additives were prepared with raw rubbers with different styrene/butadiene ratios. The mechanical and viscoelastic properties of the vulcanizates were investigated experimentally to analyze their performance as tire tread materials.Besides, atomistic molecular dynamics (MD) simulation of the three SBRs in the bulk amorphous state were performed to study the effect of microstructure on material performance. The free volume, cohesive energy density (CED), mean square displacement (MSD), and glass transition temperature (Tg) of SBR models were simulated. The simulated free volume and Tg were consistent with the experimental results. Importantly, a high correlation between the simulated micro-structural characteristics and macro-performance was obtained by a linear fit of the calculated Fsim and loss factor tan δ values of the vulcanizates at 0 and 60 °C from the dynamic mechanical thermal analysis (DMTA) spectrum. The present study hopes to provide theoretical guidance to the chain structure design of SBR for tire tread applications.

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