Effect of surface crosslinking on the Friction behavior of Tea Polyphenol stabilized Ultra-high molecular weight polyethylene

Abstract

The use of highly crosslinked ultra-high molecular weight polyethylene (UHMWPE) incorporating vitamin E (VE) as an antioxidant is widely acknowledged in the field of joint implants. While VE plays a crucial role in preventing oxidation, concerns have been raised regarding its impact on crosslink density, leading to wear performance deterioration. This study proposes the hypothesis that tea polyphenols, specifically lipid-soluble epigallocatechin gallate (IsEGCG) and epigallocatechin gallate (EGCG), may counteract the typical decrease in crosslink density caused by VE, thereby enhancing wear performance. The antioxidants were integrated into UHMWPE at a concentration of 0.2 wt%, followed by surface chemical crosslinking using di-cumyl peroxide. Surface properties, including crosslink density, roughness, coefficient of friction, and wear performance, were comprehensively evaluated. The results indicate a significantly higher crosslink density in UHMWPE blended with IsEGCG and EGCG compared to VE-stabilized UHMWPE, which exhibited a 17% reduction compared to virgin UHMWPE. The coefficient of friction increased post-crosslinking, with tea polyphenol-blended UHMWPE demonstrating a relatively higher value, confirming a highly crosslinked network structure. The wear resistance of surface-crosslinked UHMWPE stabilized with tea polyphenols was markedly superior compared to UHMWPE stabilized with VE. Additionally, a substantial presence of scratches, furrows, and flakes was observed on the surface of VE-stabilized UHMWPE in contrast to tea polyphenol-stabilized UHMWPE. These findings suggest that tea polyphenols present promising alternatives to VE for enhancing the overall performance and longevity of UHMWPE-based implants.