Characterization of UHMWPE hip cups run on joint simulators.
Characterization of UHMWPE hip cups run on joint simulators.
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在关节模拟器上运行 UHMWPE 髋杯的表征。
DOI：
10.1002/jbm.820210302
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
T. Mittlmeier
中科院分区：
文献类型：
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作者：
P. Eyerer;M. Kurth;H. A. McKellup;T. Mittlmeier
研究了HDPE-髋关节髋臼杯的密度和结晶度随从内应力表面到无应力外表面的厚度的变化。在模拟试验过程中的机械应变和化学反应的影响，以及由于预处理和储存造成的材料损坏，导致了结构的变化，如结晶度的变化所示。独立于提供的UHMWPE批次或制造商和使用的模拟器类型，单个样品组显示出相似的密度-壁厚特征曲线。红外光谱评价表明存在氧化降解，并回答了问题，哪些领域的聚合物被老化改变，哪些化合物是新形成的。还测定了特征羰基。羰基的浓度趋势相对于壁厚获得同意令人惊讶的是，以及与本地确定的密度和结晶度的趋势。由于这些化合物是通过产生稳定氧化降解产物和交联的反应形成的，因此我们确定了交联度。萃取后的可溶性成分的测定表明，材料表面的交联度低于中间。因此，在表面上，氧化断链占主导地位，而在内部，主要是交联。这些结果表明，用于模拟测试的样品在特性上具有明显的差异。一般来说，结果表明，关节模拟器中的磨损试验导致UHMWPE的性能变化，这与先前在取出的髋关节髋臼杯上获得的试验结果有很大差异。
The density and crystallinity of UHMWPE-hip cups were investigated as a function of thickness from the inner stressed surface to the unstressed outer surface. The effects of mechanical strain and chemical reactions during simulation tests, and damage of the material due to pretreatments and storage, resulted in changes of the structure, as indicated by variations in the crystallinity. Independent of either the batch of UHMWPE supplied or the manufacturer and the type of simulator used, the individual sample-sets showed a similar characteristic curve of density versus wall thickness. Infrared spectroscopic evaluations indicated the presence of oxidative degradation, and answers the question as to which areas of the polymers are changed by aging and which compounds are newly formed. The characteristic carbonyl groups were also determined. The concentration trend of carbonyl groups versus wall thickness obtained agrees surprisingly well with the locally determined density and crystallinity trend. As these compounds are formed by reactions which produce stable oxidative degradation products and also crosslinking, we have determined the degree of cross-linking. The determination of the soluble constituents after extraction showed lower degree of crosslinking on the surface than in the middle of the material. Hence it follows that on the surfaces oxidative chain scission is prevailing, whereas in the interior mainly crosslinking is developed. These results indicate that the samples used for the simulation tests had distinct differences in characteristics. Generally the results show that wear tests in joint simulators lead to property changes in UHMWPE which differ considerably from test results previously obtained on retrieved hip cups.