Stabilization of irradiated polyethylene by introduction of antioxidants (vitamin E)

Abstract

The aim of the present chapter is first to recall the general principles of stabilization. Since vitamin E is particularly adapted in the case of biomaterials, because of its low toxicity, its stabilizing mechanism and performances will be detailed, together with some experimental methods aimed at quantifying residual vitamin E after the complex elaboration process of hip. The existing literature will be reviewed so as to extract the kinetic parameters (rate constants for reactions with radicals, diffusion and solubility coefficients) necessary to perform kinetic modeling for a more complex description of the radio-thermal oxidation of PE + vitamin E. Those data will be compared with data for other common hindered phenols in order to highlight the interest of vitamin E for stabilization of hips. We will also present some practical cases of vitamin E stabilized UHMWPE and some experimental methods to detect and quantity Vitamin E in non-degraded or degraded materials.