Comparison of carbon nanotubes and graphene oxide coated carbon fiber for improving the interfacial properties of carbon fiber/epoxy composites

By designing the fiber/matrix interface, the properties of the carbon fiber-reinforced composite can be changed significantly. In this work, carboxylic-functionalized carbon nanotubes (CNTs) and graphene oxide (GO) were separately deposited on the carbon fiber (CF) surface to increase the interfacial properties of composites. The properties of fibers such as the surface topography, surface chemical composition and surface energy were examined, and the interfacial shear strength between the fibers and the matrix was examined using a microdroplet test. In addition, CNT-coated, GO-coated and pristine unidirectional carbon fiber fabrics were used to manufacture CF/epoxy composites via the vacuum-assisted resin transfer molding method, and their moisture absorption and interlaminar shear strength were measured. The results reveal that both CNTs and GO can significantly improve the interfacial properties of composites. The CNT/CF-reinforced composites have higher shear strength, and the GO/CF-reinforced composites have better humidity resistance. The interfacial reinforcing mechanisms of the composites with CNTs and GO were compared.