Abstract: In order to improve the surface infiltration of carbon fiber reinforced plastic/polymer (CFRP) and improve the bonding strength, the CFRP bonding surface was pretreated by the normal temperature and pressure air plasma treatment method, the contact angle of CFRP under different pretreatment parameters was tested, the surface energy was calculated. By using atomic force microscope, Fourier infrared spectrometer and X-ray photoelectron spectrometer, the physical and chemical properties of CFRP surface were analyzed under different treatment parameters, and 4 kinds of adhesives were used to test the tensile shear strength of bonding joints. The results show that the distance between the nozzle and the CFRP surface is 6mm, the nozzle movement speed is 50 mm/s as the best treatment condition. After plasma treatment, the contact angle between CFRP and water is reduced from 114° to 23°, and the surface can be raised from 32.49mJ/m2 to 72.19mJ/m2. Plasma treatment enhances the epoxy functional groups on the surface of CFRP, reduces the surface roughness, forms a large number of micro-scale gullies on the surface. The use of plasma treatment significantly improves the tensile shear strength of epoxy adhesive joints, so that the failures such as the interface failure and the substrate damage decrease, but pull shear strength of polyurethane adhesive joints changes little. The failure form is transformed from the composite failure of the interfacial adhesive layer to pure interface failure.

Key words: carbon fiber reinforced plastic/polymer (CFRP); atmosphere plasma preprocess; surface properties; epoxy; polyurethane