Composition effects on thermodynamic properties and interfacial structure in styrene-butadiene rubber: A combined experimental and simulation study

Understanding the structure-property relationship of styrene-butadiene rubbers (SBRs) plays a directive role in the design and optimization of relevant elastomer composite products. Herein, we investigate the properties of four types of SBRs with different compositions and the corresponding interfacial properties of SBR/silica by using atomistic molecular dynamics (MD) simulation in combination with experimental measurements. We show that a lower content of styrene causes better thermal stability of SBR, and the inclusion of styrene/vinyl restricts the movement of the polymer chain and leads to an increase in the glass transition temperature (Tg). The compo-sition effect is attributed to the presence of side groups in styrene and vinyl monomers, which noticeably affects the interfacial properties as well. The phenyl and vinyl side groups suppress the density fluctuations near the silica substrate, while promote the overall mass density in the first adsorption layer, and disturbs the ordered distribution of the main chain at the interface. The present work provides a basic understanding of the corre-lation between the composition and properties of the SBRs and SBR/silica and thus supplies theoretical guidance to the design of SBR and SBR nanocomposites for tire tread applications.

Automated summary

In this study, the properties of different compositions of styrene-butadiene rubbers (SBRs) and the corresponding interfacial properties of SBR/silica were investigated using atomistic molecular dynamics (MD) simulation and experimental measurements. It was found that a lower content of styrene improves the thermal stability of SBR, and the inclusion of styrene/vinyl leads to an increase in the glass transition temperature (Tg) by restricting the movement of the polymer chain. The presence of phenyl and vinyl side groups affects the interfacial properties and disturbs the ordered distribution of the main chain at the interface. This study provides a fundamental understanding of the relationship between the composition and properties of SBRs and SBR/silica, offering theoretical guidance for the design of SBR and SBR nanocomposites for tire tread applications.