Interface Engineering of Graphene Oxide/Natural Rubber Composites: Unraveling the Interfacial Reinforcement Mechanism...

The weak interfacial interaction between graphene and rubber has long impeded further enhancement of the performance of green graphene-based rubber materials. In this study, a dual cross-linked network was constructed in natural rubber (NR) via the functional modification of graphene oxide (GO). Two types of silane coupling agents with distinct functional groups were sequentially grafted onto the surface of GO, yielding dual-functional group synergistically modified functionalized GO (GO-MA). The interfacial structure of the composites was systematically characterized by atomic force microscopy (AFM) and differential scanning calorimetry. The results demonstrated that the dual-functional group synergistic modification strategy facilitated the formation of a dual-cross-linked interface between the GO filler and NR molecular chains. This significantly strengthened the interfacial interaction between GO and NR and promoted dispersion of the filler in the NR matrix. The excellent filler dispersion and interfacial interaction endowed the GO-MA-filled NR composites with outstanding mechanical and thermal properties. The tensile strength and tear strength of the GO-MA/NR composites reached 27.7 MPa and 31.5 N/mm, respectively, representing increases of 13.06% and 14.5% compared with those of the unmodified GO/NR composites. More importantly, molecular dynamics simulations revealed that the interfacial binding energy between the GO-MA and NR was enhanced by 102.4%, which was significantly higher than that of the single-functional group-modified GO-NH₂ and GO-SH systems. This study is expected to provide both theoretical and experimental support for the interfacial design of multifunctional group fillers and the development of high-performance green graphene-based elastomers.