Gamma radiation induced effects of compressed silicone foam

The effects of gamma radiation on mechanically-compressed, silica-reinforced silicone foam at various levels of absorbed dose and temperature were investigated in this study. The results show that irradiation temperature does not have an obvious influence upon the material morphology and properties. SEM characterization shows collapsed or deformed microstructures with increasing doses of irradiation, consistent with decreased sample thicknesses. The tensile strengths of irradiated samples increase significantly with dose level, eventually decreasing slightly with extreme exposure. Elongation at break decreases monotonically with irradiation, from a control value of 136.1 +/- 4.0% to 27.0 +/- 2.0% for samples exposed with a dose of 500 kGy at 45 degrees C. DSC studies show dose dependent crystallization phenomena and melting behaviors. The molecular weight of soluble materials decrease slightly with increasing absorbed doses. The property and morphology changes are probably attributed to the irradiation-induced crosslinking and radiolysis, the likely mechanisms for which are proposed. (C) 2015 Elsevier Ltd. All rights reserved.