The filler–rubber interface and reinforcement in styrene butadiene rubber composites with graphene/silica hybrids: A quantitative correlation with the constrained region

Silica/reduced graphene oxide (SiO₂@rGO) hybrids were fabricated by an electrostatic assembly, and subsequently, SiO₂@rGO was incorporated into styrene butadiene rubber (SBR) to fabricate SBR composites. The dispersion status of SiO₂@rGO and the filler–rubber interfacial interaction were investigated. Likewise, the amount of constrained region was quantified and the findings suggested that the greater the volume fraction of constrained region has possessed, the stronger the interfacial interaction has had. Moreover, the contribution of constrained region to the performance of composites was quantitatively analyzed by the mechanical analysis and the tube model, and the results showed that it is the effect of constrained region, rather than the contents of SiO₂@rGO, which controls the reinforcement of composites. Specifically, the higher the volume fraction of constrained region is, the better the mechanical properties of composites will be. Also, SiO₂@rGO can be utilized as novel reinforcing filler for fabricating the green tire materials with high performance.