| Abstract: | In a study aimed at the development of a polymeric material stable to the space radiation environment, the synthesis and properties of two new perfluoroaromatic polysiloxanes have been investigated. Di(pentafluorophenyl)diethoxysilane and pentafluorophenyltriethoxysilane have been prepared via Grignard synthesis from pentafluorobromobenzene and tetraethoxysilane. By hydrolytic polymerization of these intermediates, polydi(pentafluorophenyl)siloxane and polypentafluorophenylsilsesquioxane have been synthesized. The effect of ultraviolet and low-energy proton (solar wind) irradiation in high vacuum has been determined in a space-environment-simulation facility. These polymers possess excellent resistance to low-energy proton irradiation but are less stable to ultraviolet irradiation. It is suggested that the enhanced polarization of the carbon–silicon bond due to the strong inductive effect of the pentafluorophenyl groups is responsible for the relatively low ultraviolet and thermal stability of the perfluoroaromatic polysiloxanes. |
