Breakthrough in key technologies of graphene toughened carbon fiber composites in China

Carbon fiber composite materials are increasingly used in aerospace, automotive, marine and other fields due to a series of characteristics such as light weight, high strength, fatigue resistance, corrosion resistance and design. However, since the surface of the carbon fiber is smooth, inert, and chemically active, the interface bond strength between the carbon fiber and the matrix resin is low, and the interface has many defects, which often becomes a weak link of the composite material. The research team of the Chinese Academy of Sciences has recently made new progress in the key technologies of graphene toughened carbon fiber composites.

In the previous research work, it was found that the grafting of graphene nanoparticles onto the surface of carbon fiber can effectively improve the interfacial properties of carbon fiber composites. In order to realize the scale-up route of graphene-modified carbon fiber, the surface of carbon fiber is modified by graphene modified sizing agent to improve the interface performance of carbon fiber composite material. By surface modification of graphene, the researchers prepared graphene which can be stably dispersed in both aqueous solution and sizing agent. By classifying the size of graphene, surface-modified graphene was prepared, which can be stably dispersed in different In the sizing system, the stable dispersion technology of graphene in the sizing agent is successfully realized. Two kinds of graphene modified sizing agents with good stability were successfully developed by reverse conversion method and self-emulsification method, and the interfacial adhesion properties of carbon fiber composites were effectively improved. The interfacial shear strength (IFSS) was up to 92.3. MPa, and the carbon fiber sizing rate is less than 1.5%, and the saturated water absorption rate is less than 2%. The graphene is used to strengthen the carbon fiber, and the processing conditions are optimized to obtain a graphene toughened carbon fiber composite material with excellent comprehensive performance. The interlaminar shear strength of the composite material can reach 73.5 MPa; the fracture toughness of the type I interlayer is improved by 33.3. %.