Atomic insights into the impact of thermal oxidation aging on graphene/epoxy resin interfaces

• Oxygen concentration demonstrates a threshold effect on the separation behavior of GRPC . • Multi-carbon defects in GN enhance the thermal-oxidative aging resistance of GRPC . • MPS functionalized GN alters the failure mode of GRPC. Understanding the aging behavior of graphene sheet/epoxy resin interfaces under thermo-oxidative conditions is essential for optimizing the structural design and enhancing the durability of graphene-reinforced polymer composites (GRPC). This study focuses on investigating the dynamic behavior of GRPC interface structures under the combined influence of elevated temperature and oxygen exposure. To achieve this, multi-vacancy graphene (GN-MV), pristine graphene (GN), and 3-(trimethoxysilyl) propyl methacrylate-functionalized graphene oxide (GO-MPS) were employed as reinforcing materials to construct graphene sheet/epoxy resin interface systems. Molecular dynamics simulations were utilized to systematically examine the effects of temperature, oxygen concentration, and surface characteristics on the dynamic parameters of GRPC interfaces. The results reveal that the degree of interface separation increases with the number of oxygen molecules, exhibiting an initial rise followed by a decline, with the transition point influenced by the type of epoxy matrix curing system. Notably, this behavior is less sensitive to temperature variations. Interestingly, the GN-MV enhances the interfacial adhesion of GRPC, while GO-MPS significantly improves thermal-oxidative aging resistance by promoting a favorable shift in the failure mode of GRPC. The findings provide new insights and design strategies for developing high-durability GRPC and optimizing interface design.