Vulcanization Modeling and Mechanism for Improved Tribological Performance of Styrene-Butadiene Rubber at the Atomic Scale

A novel molecular model of vulcanized styrene-butadiene rubber (SBR) was developed and experimentally verified to elucidate the enhanced tribological performance of vulcanized SBR over raw SBR. Vulcanization was modeled by cross- or self-linkages of sulfur (S) atoms with carbon (C) atoms in molecular chains. Frictional models were developed for vulcanized and raw styrene-butadiene rubber-ferrum (SBR-Fe) to study the atomic behavior at the frictional interface. The results at the atomic scale show considerable reductions in the coefficient of friction (COF) and the interfacial temperature of approximately 45.8% and 13.27% for the vulcanized SBR matrix, respectively, from those of raw SBR. In addition, the relative concentration (RC), the radial distribution function (RDF) and interaction energy of the vulcanized SBR are 21.61%, 6.68% and 60.12% lower than those of the raw SBR, respectively. The resulting decrease in the real contact area, adhesion and contact temperature at the interface can significantly improve the tribological properties of the vulcanized SBR over those of raw SBR. The results of this research study show how vulcanization can enhance the tribological properties of polymer composites at the atomic scale.