Tribological investigations on virgin and accelerated aged PE-UHMW

The aim of this study is to gain a better understanding regarding the tribological wear behaviour of ultra-high molecular weight polyethylene (PE-UHMW) under certain life cycles. In order to make this quantification, virgin and accelerated aged samples were prepared and tested with a uni-directional sliding method, where the wear behaviour was observed under progressive conditions. The aging method was conducted in accordance with ASTM F2003-00. During the tribological tests, the friction coefficient was observed to have a value more than double for the aged specimens compared to the virgin ones. Although in terms of wear rate, the differences between the aged and the virgin specimens were slightly higher, the progressive testing conditions allowed to reveal the formation of different wear mechanisms at different wear cycles. Additionally, information on the polymer morphology such as degree of crystallinity, and an evaluation on the polymer degradation was done using Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR). The results obtained with these methods were correlated with the friction coefficient and the wear rate, explaining the development of wear in such conditions.