Molecular dynamics supported thermal-moisture aging effects on properties of silicone rubber

Silicone rubber materials are widely used as protective coatings in multiple fields. In this work, accelerated artificial aging tests of silicone rubber under different thermal and hygrothermal conditions were performed to better understand how temperature and humidity affected aging behavior and mechanism. It was noticed that due to the presence of oxygen molecules, the main chain of silicone rubber broke and produced free radicals, while water molecules brought hydrolysis reactions and produced silicone hydroxyl structures. Furthermore, computer aided molecular simulation was carried out to better understand the diffusion of small particles in silicone rubber materials, as well as to study how they affect the chain structure, providing support for the mechanism of aging. Finally, two lifespan prediction models were proposed respectively to determine the usage life of silicone rubber under certain temperature and humidity conditions, which provides guidance value for the use of silicone rubber.