Effect of the filler amount on the optical absorption properties and the surface features of polymeric joints based on biomedical UHMWPE welded by a Nd:YAG laser

Polymeric materials can be welded by the laser transmission welding technique in order to join two or more sheets. At the interface of the polymer sheets, the released energy induces melting that is assisted by pressure, producing a fast and resistant welding. In this research, single-lap polymeric joints of biomedical ultra-high molecular weight polyethylene sheets were realized; one of the two polymer sheets was doped, at different concentrations, with carbon nanomaterials as a laser absorbent filler. A pulsed neodymium-doped yttrium aluminium garnet laser operating in the wavelength of 532 nm and of 1064 nm with an intensity of the order of 109 W/cm2 was employed to obtain a joint at the interface between the transparent polymer and the absorbent one. The mechanical shear resistance of the prepared joints was related to the optical absorption feature of the polymeric materials. Besides, surface analyses such as hardness, roughness and wettability in different inorganic and organic fluids were presented and discussed. The result of characterization analyses indicated the best filler amount in order to have a mechanically resistant joint with surface properties also suitable for the biomedical employment.