▎ 摘　　要

Graphene oxide (GO) was grafted on the surface of carbon fibers (CFs) by a two-step diazo reaction using p-nitroaniline as the linking precursor. The strength of the covalent bond between the CFs and the GO was estimated by a gradient ultrasound method. The mechanism of the grafting reaction was verified by cyclic voltammetry. Results indicate that the surface roughness, tensile strength and elongation of the GO-modified CFs are increased by 188%, 13.2% and 12.1%, respectively. The interfacial bond strength in the epoxy matrix composite using the modified CFs as a reinforcement increased by 80.2% compared with that of the pristine CFs.