Study on Graphene-Reinforced Epoxy Solvent-Borne High-Temperature-Resistant Adhesives for Bonding C/C Composites Under Extreme Temperatures

Drawing inspiration from the bionic nacre structure, graphene was incorporated into the epoxy solvent-borne adhesive to construct a laminated architecture. At the same time, ferrocene was employed as a catalyst to induce the in situ growth of carbon nanotubes (CNTs) under high-temperature conditions. This modification endowed the epoxy solvent-borne adhesive with not only high strength in atmospheric environments but also the capability to retain considerable mechanical performance at elevated temperatures. Experimental results demonstrated that when the graphene content in the epoxy solution fell within the range of 3.2-4%, the bonding strength exceeded 3 MPa within the temperature range of 1000-1300 °C. In particular, the adhesive exhibited excellent thermal shock resistance, with no degradation in strength observed after 15 thermal shock cycles at 1300 °C. Such exceptional performance was attributed to the formation of interlaminar CNTs generated after high-temperature treatment. Scanning electron microscopy (SEM) observations clearly revealed the laminated graphene sheets and in situ grown CNTs, confirming the feasibility of the strategy to enhance bonding efficacy by mimicking the nacre structure. This approach represented an innovative breakthrough for further research on the application of the "brick-and-mortar" structure in the bonding layer and the in situ growth of CNTs among lamellar graphene, while also providing detailed supporting data.