Effect of radiation dose on depth-dependent oxidation and wear of shelf-aged gamma-irradiated ultra-high molecular weight polyethylene (UHMWPE)

•The relationships between radiation dose, OI and wear properties are illustrated.•When OI<1, the wear rate is mainly affected by radiation dose and decreases with it.•When 13-except for the 1000 kGy sample-the wear property is severely deteriorated.•High irradiation (above 200 kGy) is capable of lowering the oxidation of UHMWPE.

The effect of radiation dose on the depth-dependent oxidation and wear of shelf-aged gamma-irradiated UHMWPE was investigated in this paper. FTIR, micro-indentation, pin-on-plate wear tests and SEM imaging were carried out at three representative regions (surface, subsurface and center) for each sample. The experimental results show that when the oxidation index (OI) <1, the wear rate is clearly affected by the radiation dose (crosslinking density). When 13 – except for the 1000 kGy specimen – the wear resistance is severely deteriorated and the relationship with the radiation dose is difficult to predict. Results suggest that higher irradiation (above 200 kGy) is capable of lowering the oxidative degradation of UHMWPE.