Development of High-Temperature-Resistant Elastomeric Sealant.

摘要

A program aimed at synthesizing hydrofluorocarbon-fluorosilicone or -silicone polymers is reported. The copolymers were desired as bases for formulating improved pressure sealants for advanced aircraft. The free radical catalyzed addition of hydrogen sulfide to vinylsilanes was investigated. The desired mercaptans could not be obtained;only sulfide formation was observed. A mercaptan-substituted acetoxysilane was synthesized and condensed with dehydrofluorinated Viton. Combination of this product with acetoxy-functional fluorosilicones could not be attempted due to the instability of the product. A low molecular weight dimethylsilicone with mercaptan end-groups was synthesized and used to cross-link dehydrofluorinated Viton. The copolymer formed was not suitable for sealant use. A hydrofluorocarbon-fluorosilicone cocured product,described previously,was investigated further. It was not suitable for sealant use. (Modified author abstract)