Buchanan F J, Shipway P H
School of Mechanical and Manufacturing Engineering, The Queen's University of Belfast, N. Ireland, UK.
Biomaterials. 2002 Jan;23(1):93-100. doi: 10.1016/s0142-9612(01)00083-7.
The ageing behaviour of ultra-high molecular weight polyethylene (UHMWPE) has been studied following gamma irradiation (25 or 40 kGy) in air. Accelerated ageing procedures used elevated temperature (70 degrees C) and/or pressurised oxygen (5bar). Shelf-aged UHMWPE was also studied. The variation in surface density and mechanical properties were determined following the various sterilisation and ageing treatments. Microabrasive wear testing was also performed. Wear rates were found to correlate well with stress at break for sterilised and aged UHMWPE but not with elongation to failure. It is proposed that the wear mechanism is fracture dominated and occurs following some disentanglement of the polymer chains. Wear also depends upon embrittlement of the surface layer due to its processing and ageing. Elongation to failure in a tensile test is not a good measure of this embrittlement whereas the microabrasion test provides more surface sensitive information concerning this property.
在空气中进行γ辐照（25或40千戈瑞）后，对超高分子量聚乙烯（UHMWPE）的老化行为进行了研究。加速老化程序采用了高温（70摄氏度）和/或加压氧气（5巴）。还研究了货架期老化的UHMWPE。测定了各种灭菌和老化处理后的表面密度和机械性能变化。还进行了微磨料磨损测试。发现磨损率与灭菌和老化后的UHMWPE的断裂应力密切相关，但与断裂伸长率无关。有人提出，磨损机制以断裂为主，发生在聚合物链发生一些解缠之后。磨损还取决于由于其加工和老化导致的表面层脆化。拉伸试验中的断裂伸长率不是这种脆化的良好指标，而微磨损试验提供了更多关于该性能的表面敏感信息。
