Ultra-high molecular weight polyethylene .1. Mechano-oxidative degradation

Mechano-oxidative degradation occurs during microtoming of unstabilised ultra-high molecular weight polyethylene (UHMWPE). The oxidised species formed are shown to be esters and, to minor extent, acids. A mechanism is proposed in which the displacement of the blade of the microtome creates primary radicals in pairs by stretching of the interpenetrating chains. Oxidation of one of these radicals, followed by coupling of the pair, yields a dialkyl peroxide which in turn has been shown to decompose to ester via a concerted mechanism. (C) 1997 Elsevier Science Limited.