“One method to improve the wear resistance of UHMWPE is to increase the degree of crosslinking of the polymer using ionizing radiation, such as gamma ray or electron beam irradiation.  Ionizing radiation results in the breaking of carbon-carbon and/or carbon-hydrogen bonds, and the formation of free radicals, at the molecular level of the polymer. In the absence of oxygen, these free radicals can form carbon-carbon crosslinks between adjacent molecules, returning to a stable molecular structure.  This stabilization process can be accelerated by elevating the temperature of the irradiated UHMPWE, below, near, or above the melt temperature of the UHMWPE.  Based on numerous wear studies from multiple laboratories, the wear resistance of UHMWPE generally increases as the degree of crosslinking of the polymer increases.”
(Cheal, US Patent 7,803,310, 9/28/2010)

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