Laser transmission welding of Poly(vinyl chloride) and polyamide 66 based on green femtosecond laser surface modification

Abstract

To improve the bonding strength of unweldable poly(vinyl chloride) (PVC) and polyamide 66 (PA66), a surface treatment method using green femtosecond laser (GFL) to modify PVC before welding was proposed in this study. The experiments of GFL surface modification, 1940 nm laser transmission welding (LTW), mechanical properties test and related characterization were carried out. The effects of GFL parameters on the physical and chemical properties of the modified surface and the bonding strength of the dissimilar joints were investigated in detail. The bonding mechanism of PVC/PA66 joints was analyzed comprehensively. The results showed that laser modification induced the deposition of many oxygen-containing functional groups on the PVC surface. These oxygen-containing functional groups form a highly polar modified layer on the surface, thereby improving the miscibility and welding performance of PVC/PA66. Finally, the modification and welding parameters were optimized based on the response surface methodology (RSM), and the maximum shear strength was 8.9 MPa.