Effect of laser surface treatments on a thermoplastic PA 6/carbon composite to enhance the bonding strength

Abstract

Adhesive bonding is an appropriate method to assemble structural composite components without a machining process. Compared with the properties of the carbon fiber reinforced thermoset polymer (CFRP), the carbon fiber reinforced thermoplastic polymer (CFRTP) have advantages, such as recyclability and superb impact, corrosion and temperature resistance. However, CFRTP have a low bonding strength with structural adhesives. In this study, a laser treatment was applied to an epoxy based CFRP and polyamide 6 (PA 6) based CFRTP surfaces to improve the adhesive bonding strength. Shear and tensile adhesive bonding tests were performed, and the mechanism of the laser treatment was investigated by the failure mode, surface free energy and Fourier transform infrared spectroscopy (FTIR) analyses. The adhesive bonding strengths of the CFRP and CFRTP were significantly improved by the laser treatment, and each wettability and functional groups is increased.