Perfluoroalkylene Oxide Polymers as High-Temperature Sealants

Photolysis of perfluoroether diacid fluorides and chain-extension of fluorocarbonether-bridged chlorosilanes have been investigated as routes to a high-temperature integral fuel tank sealant polymer. Six different fluorocarbon ether-bridged chlorosilanes have been prepared and their polymerization to silanol-ended fluorccarbon ether-bridged siloxanes investigayed. Sealant compounds prepared from the siloxane polymers have long term stability in air up to 400 F. Substitution of trifluoropropyl groups on silicon is necessary to achieve the desired jet fuel resistance. Aging of two sealant compounds containing trifluoropropyl groups on silicon indicate that they will be useful for certain periods of time up to 500 F in a jet fuel environment. However, more research is necessary to firmly determine the upper temperature limit.