Effect of electrochemical oxidation degree of carbon fiber on the interfacial properties of carbon fiber–reinforced polyaryletherketone composites

Electrochemical oxidation of carbon fiber (CF) is used to enhance the interfacial adhesion of CF-reinforced polyaryletherketone (CF/PAEK) composites. The effect of current intensity parameter on surface structure of CF and interfacial properties of the corresponding thermoplastic composites are deeply investigated. The results show that the current intensity in the range of 80 A–300 A does not lead to a decrease in the mechanical property of CFs. When the current intensity is 200 A, CF/PAEK composites have the highest interfacial performance, which is mainly due to the improvement of CF surface roughness, wettability, and oxygen content. In addition, the degree of graphitization of CF surface is also a crucial factor affecting the interfacial properties of CF/PAEK. The higher the content of carboxyl groups, the more disordered the structures exist on the CF surface, which are not conducive to the strong adhesion of CF to PAEK resin. Therefore, balancing the wettability and graphitization degree of the CF surface is the key to enhancing the CF/PAEK interfacial properties by electrochemical treatment techniques.