シリコンゴムのγ線照射効果

抄録

Radiation effects on methyl silicone rubber and phenyl silicone rubber are studied by the use of gamma rays of cobalt-60.
With increasing radiation dose, irradiated samples become harder eventually turning glass-like; Young's modulus, breaking stress and average stiffness are all enhanced; maximum degree of elongation and weight swelling ratio are reduced. The change in these values is smaller for phenyl silicone rubber than for methyl silicone rubber which is considered attributable to protective effect of phenyl radical against radiation-induced crosslinking. From Young's modulus and weight swelling ratio, number of crosslinks in pure silicone rubber was calculated, the number being found proportional to radiation dose. Different methods of calculating this number gave more or less different values even for the same sample, but when the same method was applied, phenyl silicone rubber was found to have a smaller number of crosslinks than methyl silicone rubber.