DIELECTRIC MATERIALS FOR HIGH TEMPERATURE EVALUATION
Rept. for 16 Dec 1963-30 Apr 1964
THIOKOL CHEMICAL CORP DENVILLE NJ REACTION MOTORS DIV
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Carborane siloxane polymers were studied as thermally stable materials. Methods of polymerization to obtain high molecular weight linear polymers were investigated. Cohydrolysis of dimethyldichlorosilane and 4- carboranylbutyl- methyldichlorosilane and solvent fractionation of the products yielded linear polymers of 7000-14,000 molecular weight. This preparation was scaled up to produce 21 lb of polymer which upon fractionation yielded approximately 10.5 lb of high molecular weight product. A higher molecular weight carborane siloxane elastomer was prepared by addition of butenylcarborane to a silicone gum that contained silyl hydrogens. Addition occurred readily when the reaction sites were uniformly separated but was sterically hindered when the sites were randomly located. Carborane siloxane polymers were cured, using ethoxysilane curatives and metal octoate catalysts, to investigate potential applications in varnishes, laminates, elastomers and plastics. The thermal properties of uncured and cured carborane siloxane polymers were investigated in an application study. Tests in simulated sealed electric motors at 185C showed no corrosion of the carbon brushes due to the carborane siloxane polymer.
- Inorganic Chemistry