Effect of laser cleaning of carbon fiber-reinforced polymer and surface modification on chemical activity and bonding strength

Bonding has been used to repair carbon fiber-reinforced polymer (CFRP) materials. However, research has shown that resin residue on the surface of CFRP can cause adhesion problems. Therefore, a reliable surface cleaning procedure is necessary to remove the resin residue before bonding. In this paper, the surface resin was removed by laser cleaning, while the surface properties of CFRP were improved. A pulsed laser cleaning experiment was designed to study the chemical activity and bonding strength of CFRP treated by laser with different laser power and scanning speed. The results showed that as the contact angle of the material surface decreased, chemical activity and adhesive properties were improved. The surface pretreated with laser power of 16 W (scanning speed of 1500 mm/s) had no resin residue and the best adhesive properties; the bonding strength was 1.6 times higher than that of the untreated surface, and the failure mode was dominated by a cohesive damage mode.