URETHANE-SILICONE INSULATION DEVELOPMENT.

A low-density polyurethane-silicone insulation has been developed for use in protection of space vehicles which must withstand cryogenic and high-temperature environments. Its basic composition consists of a flexible open-cell polyurethane foam matrix modified by the addition of varying percentages of low-viscosity methyl-phenyl silicone resin. With the increase in the silicone resin content, a corresponding increase in elevated-temperature capability is achieved. The material has been characterized for thermal properties and also has been evaluated under a simulated vehicle flight environment. Compared to commercial insulation products, polyurethane-silicone material exhibits competitive thermal properties. The low-cost commercial packaging grade polyurethane foam used coupled with the capability of applying the insulation to complex surfaces by means of simple vacuum bag techniques at ambient temperature, should result in minimizing the overall insulation application cost.