| 초록 |
Ultra-high molecular weight polyethylene (UHMWPE) has been used as a bearing material in total joint replacements. γ-irradiation at a minimum dose of 2.5 Mrad is the common technique to sterilize UHMWPE. Chain scission and the formation of free radicals followedy by crosslinking are well-known phenomena occurring in irradiation. We investigated the effects of irradiation on the properties of UHMWPEs crystallized by slowl-cooling and quenching. Samples were irradiated at doses of 1, 5, and 10 Mrad in N2.The irradiated samples were heat-treated in a vacuum oven in order to stabilize the residual radicals related to oxidative degradation. We confirmed by ESR that heat treatment led to the considerable reduction in the amount of residual radicals. DSC crystallization exotherms showed different phenomena according to the initial morphology prior to irradiation. The analysis of DMA spectra gave us the further understanding of the morphology of the irradiated UHMWPE, especially in the molten state. Tensile properties were well correlated with the previous researches. |
