Static and dynamic characterization of biomedical polyethylene laser welding using biocompatible nano-particles

In this research, polymeric joints of Ultra High Molecular Weight Polyethylene (UHMWPE) sheets were realized and welded by a diode laser operating at 970 nm wavelength. One of the polymer sheet was doped, at different concentrations, with nano filler (carbon, titanium and silver nano-particles) in order to enhance the absorption coefficient at the laser wavelength. Laser operated in repetition rate with a maximum pulse energy 100 mJ, for times of the order of 1-60 s transporting the light trough a fiber with 300 μm diameter. The laser light has been transmitted by the transparent first polymer and absorbed on the face of the second doped polymer. At the interface of the two polymer foils, 0.5 mm thickness each, the released energy induces melting, assisted by pressure, producing a fast and resistant welding. Single lap and double lap geometries have been performed and studied by means of mechanical static (shear stress) and dynamical analysis. Effect of the different particles nature on the mechanical features of the joints has been evaluated. Morphological observation of the jointed areas are presented and discussed. Joints could be useful in biomedical field for their special features.