MECHANICAL RESPONSE OF PMMA UNDER COMPRESSION STRESS AT 300 K AFTER EXPOSURE TO (CO)-C-60 GAMMA-RAYS

In this work, the variation with the irradiation dose of the yield str ess in polymethylmethacrylate exposed to gamma radiation was studied a t different strain rates. Doses of 0, 50, 100, 150 and 200 kGy were em ployed. Compressive tests were made with strain rates between 1.4x10(- 3) s(-1) and 3.5x10(2) s(-1). The dependence of the compressive yield stress with the irradiation dose was considered as a consequence of th e dependence of Young's modulus. Finally, the results were qualitative ly analyzed within the scope of chemical degradation theories in polym ers.