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Biomedical grade UHMWPE double lap joint, welded by a diode laser, has been mechanically characterized by static and dynamic tests. A nanocomposite sheet (UHMWPE filled with low carbon nanoparticles amount) was interposed between two polymeric sheets in order to absorb the laser light, sealing the sheets by means of a melting process. Fatigue test has been performed in the joint with 0.016 wt% of carbon nanofiller for its best mechanical static resistance among those studied. Its fatigue limits resulted to be equal to 22000 cycles. Breaks occurred at the 2nd welded interface, where a poor melting process weakens the entire joint. [ABSTRACT FROM AUTHOR]

Polymeric joints, made of biomedical polyethylene (UHMWPE) nanocomposite sheets, were welded with a diode laser. Since polyethylene does not absorb laser light, nanocomposites were prepared containing different percentages by weight of titanium dioxide as it is a laser absorbent. The joints were first analyzed with static mechanical tests to establish the best percentage weight content of filler that had the best mechanical response. Then, the nanocomposites containing 1 wt% titanium dioxide were selected (white color) to be subjected to fatigue tests. The experimental results were also compared with those obtained on UMMWPE with a different laser light absorbent nano filler (carbon, with greater laser absorbing power, gray in color), already studied by our research team. The results showed that the two types of joints had an appreciable resistance to fatigue, depending on the various loads imposed. Therefore, they can be chosen in different applications of UHMWPE, depending on the stresses imposed during their use. [ABSTRACT FROM AUTHOR]