The role of simulated body fluid and force on the mechanical and tribological properties of α-tocopherol stabilized UHMWPE for biomedical applications

In this study, the effects of simulated body fluid (SBF) and force on the mechanical and tribological properties of ultrahigh molecular weight polyethylene (UHMWPE) stabilized with α-tocopherol (α-T/UHMWPE) were evaluated. The crystallinity, chemical composition, wettability and wear mechanism were examined to understand the changes in the observed properties. The experimental results showed that the crystallinity and O/C ratio increased by 13.4 and 7.0%, respectively, after immersing α-T/UHMWPE in SBF for one year. At the same time, these properties changed slightly after the impact of force as well as degradation. These changes resulted in reducing the mechanical properties and contact angle after immersion with α-T/UHMWPE in SBF for one year. The coarse surface led to lower contact angle, higher initial friction coefficient and lower creep resistance due to force and degradation, whereas other mechanical properties changed slightly. The wear changed from scratches and furrows in α-T/UHMWPE or after the impact of force and degradation to furrows, flakes and ruptures after immersion in SBF for one year. These changes in properties in α-T/UHMWPE were less than that in pure UHMWPE owing to oxidation and wear resistance of UHMWPE that were improved by α-tocopherol.