Silicone rubber RTV-1 aging in the presence of aqueous salt

In our previous research on the effect of salt on aging of Room Temperature Vulcanized one-component (RTV-1) silicone rubber material we reported a strong relationship between losses in material mass and hydrophobicity, and potentially significant changes in the mechanical properties of the materials. This is further investigated in the present study, which examines the effects of aging in aqueous salt solution at elevated temperature on the hardness, hydrophobicity, and damage of a selected high quality RTV-1 material. A simple mechanical approach is suggested, which could be used in service to evaluate the amount of aging of RTV materials by correlating changes in hardness with surface conditions such as hydrophobicity. In addition, a new model of aging of RTVs based on the formation of hypochlorous acid in the presence of saltwater on energized silicone rubber surfaces is suggested and supported by Molecular Dynamics (MD) simulations. The diffusion rates of hypochlorous acid, salt ions, water, and nitric acid were numerically compared to determine which aging compound could be primarily responsible for material damage to RTVs under both laboratory and in-service conditions.