Stabilization of highly crosslinked ultra high molecular weight polyethylene with natural polyphenols

In the present work, dodecyl gallate (DG) and gallic acid (GA) were blended with UHMWPE and consolidated by compression moulding prior to e-beam irradiation. Stabilisation of highly crosslinked UHMWPE with these polyphenols was examined by tracing post-irradiation oxidation kinetics of UHMWPE at room temperature with Fourier transform infrared (FTIR) spectroscopy, in comparison to highly crosslinked vitamin E (VE)-blended and virgin UHMWPE. Phenol loss upon e-beam irradiation depended on the polyphenol chemistry and compatibility with the polyethylene matrix: the oleophilic DG and VE showed higher phenol loss than GA. Nevertheless, all the antioxidant-containing materials exhibit improved oxidation stability compared to virgin material. The formation kinetics of ketones, hydroperoxides, carboxylic acids, esters, and ketoacids were analysed in detail over time in order to understand the effect of polyphenols on the oxidation mechanism of highly crosslinked UHMWPE. Our results suggest that these polyphenols show limited phenol loss and are protective for highly crosslinked UHMWPE, which may be promising alternative for UHMWPE biomaterials with improved stability.