The study of laser transmission joining PA66 and PVC with large compatibility difference

Abstract

On account of the large compatibility difference between Polyamide 66 (PA66) and Polyvinyl chloride (PVC), it is difficult to weld them directly by laser. The magnetron sputtering technology is introduced in this paper by which the transparent PVC is successfully welded with PA66 sputtered a 20μm-thick aluminum thin film as the transition and absorbed layer. In terms of the generation of bubbles, the distribution of aluminum atoms, the increasing of polymer surface free energy and the formation of new chemical bonds, this paper analyzes the mechanism why the two different materials can be welded successfully. The influences of bubbles and aluminum atoms on the performance of the joints are investigated via the optical microscope, revealing the micro anchor effect of high pressure homogeneous bubbles generated in the welding process and the improvement of material compatibility resulting from the addition of aluminum atoms. The surface contact angle meter is used to analyze the effect of coating on the surface free energy of polymer, and X-ray Photoelectron Spectrometer (XPS) is used to detect the chemical bond information of fracture sections on PVC. It is revealed that the increasing of coated PA66 surface free energy and the generation of new chemical bonding (Al-Cl) are the key to weld successfully. Finally, the mathematical model of process parameters is established by response surface method, and the optimal combination of process parameters is obtained.