Positron annihilation and ion beam analysis of ion-bombardment-induced hydrogen release and oxidation of ultra high molecular weight polyethylene

Ultra high molecular weight polyethylene was bombarded with He+ and Ar+ ions to fluences ranging from 1013 to 2×1016 ions/cm2. Rutherford backscattering and nuclear reaction analysis were applied to study mechanism of oxygen uptake and hydrogen release induced by ion beam bombardment. The influence of ion bombardment on positron annihilation lifetime parameters is also discussed. Hydrogen release was observed with increasing ion dose and was correlated to the ion stopping power. An important effect observed, was the rapid oxidation of samples after exposure to air.