Effect of accelerated aging on the thermo-mechanical behavior and biotribological properties of an irradiation cross-linked GO/UHMWPE nanocomposite after VE diffusion

In this work, the influence of accelerated aging on the thermo-mechanical behavior and biotribological properties of an irradiation cross-linked GO/UHMWPE nanocomposite after VE diffusion was investigated, including through differential scanning calorimetry (DSC), gel content, FT-IR characterization, oxidation index, ball indentation hardness, and especially the biotribological properties. The results show that accelerated aging increased the melting point and crystallinity of the nanocomposite, but resulted in a decrease in thermal stability and gel content. The oxidation index increased by 60.2% and the hardness decreased by 18.1%. In particular, the friction coefficient and wear rate increased by 99.5% and 87.4% respectively. A simple VE diffusion process had no obvious effect on the melting point, crystallinity, thermal stability, gel content and hardness, but the oxidation resistance and biotribological performance were improved to a certain extent. On the contrary, when VE exists in the accelerated aging process, the above properties are significantly improved. In particular, the oxidation index decreased by 21.1%, and the friction coefficient and wear rate decreased by 33.7% and 26.4%, respectively. After accelerated aging, fatigue wear and abrasive wear are the main wear forms, while VE plays the function of reducing friction and wear. Besides, the anti-friction and wear resistance mechanism of VE during the accelerated aging process was also illustrated.