Abstract: Surface treatment is one of the most important procedures for the preparation of the high performance carbon fiber. The morphology of the surface-treated PAN carbon fiber was characterized in terms of AFM, SEM, XPS and XRD. And the modification mechanism of the electrochemical oxidation method was also discussed. Results show that the weaker layer of carbon fiber surface is removed by the electrochemistrical etching. As compared with the untreated carbon fiber, the grooves after treatment become widened and deepened, and the surface roughness is also increased one-fold. The functional groups on the carbon fiber surface are increased after the chemical oxidation of electrochemistry, as confirmed by that the (O1s+N1s)/C1s atomic ratio is increased by 9.7%. The physical and chemical double effectiveness mechanism is put forward that the physical and chemical state of the carbon fiber surface can be improved simultaneously by the electrochemical oxidation.

Key words: carbon fiber, electrochemical oxidation, surface modification, mechanism