Space environmental effects on silicone insulating materials

In general, the thermal-vacuum weight loss of silicone materials is exceptionally low, regardless of preconditioning. The fact that most silicones do not contain the plasticizers, antioxidants, extenders and other additives commonly used in many organic materials significantly contributes to their superior performance in simulated space environment. In cases such as volatile components condensing on optical surfaces, where even a slight amount of vacuum outgassing might be critical, any of several processing techniques can be effectively applied to further reduce weight loss. A certain amount of gases and moisture will be adsorbed from the atmosphere after the sample has been removed from vacuum. However, this regained weight will be rapidly removed by further vacuum treatment. In addition to low weight loss characteristics, silicone materials have exhibited exceptional retention of physical and electrical properties after combined high temperature and vacuum exposure, and have displayed favorable resistance to ultraviolet and particle radiation.