Effects of ionizing radiation sterilization treatment on medical use plastic materials

Abstract

Irradiation of medical-use polymers causes chemical and physical changes in plastic polymer materials. The effects of ionizing radiation on these materials have been studied; the respective literature is reviewed to provide the basis for a safety evaluation of plastics exposed to irradiation sterilization treatment. Permeability of plastic films is generally not affected; deterioration of mechanical properties, that may occur with certain polymers, can usually be controlled with adequate stabilizers; and changes in infrared and UV/VIS spectra are observed with different irradiation doses. Gaseous radiolysis products include hydrogen, methane, CO2, CO, hydrocarbons, and, for chlorine-containing polymers, hydrogen chloride. A range of volatile products, mainly hydrocarbons, alcohol, aldehyde, ketone, and carboxyllc acids, has been characterized for low density polyethylene and polypropylene, but other important materials, e.g., polystyrene and poly (vinyl chloride), are less well-investigated. Radiation-induced changes are shown to depend on the chemical structure of the polymer, on the composition (additives) and processing history of the plastic, and on the irradiation conditions.