Fig. 2A–B.

A diagram illustrates the oxidation scheme of UHMWPE and the stabilizing mechanisms of vitamin E. (A) Due to radiolytic bond scission, free radicals are produced in irradiated UHMWPE, which react with oxygen and trigger the oxidation cascade (Reactions 1–4). Oxidation is accompanied by chain scissioning, deteriorating its mechanical properties. It is believed α-tocopherol can stabilize peroxy radicals formed by oxidation and can also directly react with alkyl macroradicals (Reactions 5 and 6). (B) The formed tocopheryl product can in turn interact with another alkyl macroradical, furthering the stabilizing effect.