Icosahedral carboranes. XIX. Preparation of linear trifluoropropyl‐substituted polycarboranylenesiloxanes

Abstract

A series of linear trifluoropropyl‐substituted polycarboranylenesiloxanes with molecular weights between 3,500 and 13,000 has been prepared by the tetramethylguanidine–sulfuric acid‐catalyzed condensation of various silanol‐terminated monomers as well as by simple hydrolytic condensation of m‐B10H10C2(SiMePfOSiMePfCl)2 and B5H5C2‐(SiMePfCl)2 (where Pf = CH2CH2CF3). The polymers containing the C2B5H7 and C2B10H12 carboranes range from hard glasses to viscous gums and rubbers, are more thermally stable than fluorinated silicones with comparable resistance to solvents, and are potentially useful as high‐temperature fuel tank sealants.

Boron-Containing Polymers—The Carboranesiloxanes

“…All the above preparative routes were investigated, 21 i.e., ferric chloride-catalyzed condensation of chloro-and methoxyterminated monomers, hydrolytic condensation of chloroterminated monomers, and condensation of hydroxyterminated monomers. In comparison with the completely methyl-substituted polymers, however, the molecular weights attained were comparatively low.…”