Synergistic effect of nano-SiO2 and small-sized graphene oxide on carbon fiber/epoxy composite

The poor interface of carbon fiber (CF) reinforced composites has long been one that researchers want to facilitate. A hierarchical structure of nano-SiO2 and small-sized graphene oxide (sGO) on CF was constructed by a layer-by-layer method. The electrochemically treated CF was evenly coated with sGO sheets as a medium layer, which made nano-SiO2 uniformly spread over CF by electrostatic adsorption. The hierarchical structure could provide the synergistic reinforcement on the mechanical properties of CF composite by improving interface adhesion, mechanical interlocking, and chemical bonding. The interlaminar shear strength value of SiO2-sGO-CF/epoxy composite reached 71.1 MPa, which was increased by 33.45% compared with the electrochemical etching CF/epoxy composite. The results show that the sizing of sGO and nano-SiO2 plays a positive synergistic effect by hierarchical reinforcement.