REGULARITIES OF THE CHANGE IN STRESS-STRAIN PROPERTIES OF POLY(METHYLMETHACRYLATE) AND EPOXIDE POLYMERIC NETWORKS UNDER PROTON AND GAMMA-IRRADIATION

A new approach based on analysis of regularities of the change in tens ile strength of samples of poly(methyl methacrylate) and an epoxy resi n irradiated with accelerated protons is suggested to predict the radi ation-induced change of performance characteristics of polymeric mater ials under the action of radiation. This procedure involves the determ ination of track parameters of ionizing particles, the use of the perc olation theory to obtain the critical values of fluences or absorbed d oses resulting in deterioration of polymer macroproperties, and, final ly, in arrangement of a crucial experiment and comparison of its resul ts and those of calculations. The type of change in the stress-strain properties of the epoxide samples irradiated with accelerated protons agrees satisfactorily with tentative calculation results; however, in the case of poly(methyl methacrylate) the experimental and calculated data differ, which may be a consequence of factors such as ''long-rang e effects,'' etc., that were neglected in model calculations.