Precisely adjusting the interface adhesion of carbon fiber/epoxy composites by regulating the micro-configuration of graphene oxide nanosheets on the fiber surface

Different micro -configurations of graphene oxide (GO) nanosheets on the carbon fiber (CF) surface, including the distribution and size, endow CF -GO enhanced microstructure and physiochemical characteristics of the CF/epoxy (CF/EP) composites. In order to investigate the relationship between the GO micro -configuration and the interfacial adhesion of the CF/EP, here, polyether imide (PEI) -GO heterogeneous reinforcement was grafted onto the CF surface (CF -PEI -GO) by precisely modulating the mass ratio of CFs to GO. The micro -configuration and properties of the CF -PEI -GO hybrids, together with the thickness and modulus variation of the interface layer are investigated, in order to make certain on the enhancement mechanisms of both interfacial and mechanical performances. Optimal performances of the CF-PEI-GO/EP composites are achieved with a CF/GO mass ratio of 40:1. The uniformly "upright " distribution of moderate -size GO on the CF surface induces a synergistic effect of improved mechanical interlocking, chemical bonding, high wettability, and effective interface adhesion, which are stemmed from higher surface roughness, more active functional groups, higher surface energy, and wider interface thickness with gradient descent modulus. This work presents a valid, practical strategy to precisely control the interfacial adhesion of the CF/EP composites by adjusting the micro -configuration of 2D materials on the fiber surface.