Employment of Carbon Nano Materials for the Welding of Polyethylene Joints with a Nd:YAG Laser

Single lap polymeric joints can be obtained using laser welding overlapping two polymeric sheets one laser transparent and the other laser adsorbent. In this paper we have employed crystalline carbon nano materials (in amount of 0.2-0.5- 1.0% wt) as filler to enhance the absorption of polyethylene (UHMWPE type). A Nd:YAG laser operating at 1064 nm was used as power source to make the welded joints. Morphological, mechanical and calorimetrical tests were carried out to study the strength of the made joints. Serious attention was paid to find the best compromise between exposure time to laser light and filler amount. We found that in the optimal condition (with a 0.2%wt of filler and 60 seconds of exposure time) the joint exhibits a good shear strength with a polite and regular welded area. In fact, the best conditions guarantee a proper absorption power of the laser light and a deep interpenetration of the chains between the two polymeric sheets without any damage.