| Summary: | 碩士 === 國立陽明大學 === 醫學工程研究所 === 100 === UHMWPE is widely used for artificial hip and knee joints because of its high wear resistance, low friction and high toughness. However, the wear problem induced by the aging of the material remains one of the main causes which restricted the longevity of an artificial joint. Recently, technique by doping α-tocopherol, an anti-oxidant, into UHMWPE has been developed to improve the aging problem. However, although the presence of α-tocopherol can reduce the level of oxidation, it affects the mechanical properties of the material as well. In this study, we used a small punch system, a pin-on-flat system, and a wear test system to test the mechanical properties of UHMWPE and to clarify the effects of α-tocopherol and Cross-linking on the performance of UHMWPE. The mechanical tests showed that by adding α-tocopherol can effectively improve the decrease in Young’s Modulus induced by cross-linking. Cross-linking also decreases the crystallinity and density of the material substantially and causes the deterioration of the mechanical properties. By adding α-tocopherol, the decrease in crystallinity and density due to cross-linking were improved and in consequence stabilize the microstructure of the materials. Friction and wear tests show that friction coefficient and wear factor both decreases by cross-linking while the increases by adding α-tocopherol. By dopping α-tocopherol , the extent of increase in wear factor due to aging can be reduced.
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