Abstract：Silicone rubber foams are widely used in industrial and biomedical fields. When exposed to γ radiation, silicone rubber foams undergo chemical changes and show degraded mechanical performances. Hence, it is essential to establishment a radiation dose-related mechanical model to describe the mechanical behavior of silicone rubber foams under γ radiation field. In this work, the uniaxial compression behaviors of silica reinforced silicone rubber foams under γ-radiation exposure with a wide range of 0~1000 kGy were investigated by mechanical tests and theoretical modeling. Experimental results show that γ irradiation results in a significant hardening effect on the silicone rubber foam. The initial compression modulus and the stresses for a particular strain both increase linearly with γ radiation dose. The radiation-induced hardening behavior is ascribed to the predominated chemical crosslinking reactions of silicone rubber matrix, which is confirmed by solvent swelling measurement. The crosslink density of the silicone rubber matrix increases linearly with radiation dose. Scanning electron microscope shows that the void structures of silicone rubber foam do not change under the irradiated environment. Based on experimental observations, the Ogden Hyperfoam model is generalized to describe the hyperelastic response of silicone rubber foams over the wide range of γ radiation, by correlating model parameters with radiation dose. Initial shear modulus related parameters are redefined as a linear function about radiation dose, and strain hardening exponents and Poisson ratio related parameters are independent of radiation dose. In the end, model parameters for the second order of the generalized Hyperfoam model are estimated based on uniaxial compression test data, and the prediction ability of the radiation-related model is verified. Results indicating that our model is suitable to characterize the large deformation behavior of silicone rubber foam for the investigated dose range. The model can help to prepare silicon rubber foam materials with high-performance under γ irradiation condition, and design optimized silicone rubber foam structures used in γ irradiation environments.
2020, Vol. 41 
