Synergistic Effects of Gamma Irradiation, Tensile Stress and Moisture on the Radiolysis of Silicone Foam

The present work involves the investigation of the synergistic effects of gamma irradiation, tensile stress and absorbed moisture on the radiolysis behaviors of silicone foams by experiments and theoretical simulations. For both the pristine and dehydrated samples, the permanent tensile set increases with the initial tensile strain. Further analysis uncovers that the dehydrated samples exhibit greater permanent tensile sets, lower further elongation and higher Young’s modulus than the counterparts of the pristine samples with the same initial tensile strain and gamma dose, verifying the vital synergistic effects on crosslinking network and aggregation structures caused by moisture and gamma radiation. The synergistic effects unveiled by reactive molecular dynamics at the atomic scale are due to the moisture-induced neutralization and stabilization of the macromolecular radicals. The steric hindrance of moisture located at the interface of silica and polymer chains also conduces to the observed synergistic effects due to the inhibited crosslinking reactions.