Precise Synthesis of Poly(silphenylenesiloxane)s with Epoxy Side Functional Groups by Tris(pentafluorophenyl)borane as a Catalyst

Abstract

1,ω-Dimethylhydroxysilyl, -dimethylhydrosilyl, -dimethylmethoxysilyl -terminated tetramethylsilphenylenesiloxane prepolymers were prepared by sequential palladium-catalyzed dehydrocoupling polymerization of 1,4-bis(dimethylsilyl)benzene with water, reduction with lithium aluminium hydride, and palladium-catalyzed methanolysis. 1,4-Bis[(glycidyl- or cyclohexene oxide-functionalized alkyl)methylhydrosilyl]benzene and methyldimethoxysilanes with the same epoxy groups were synthesized by hydrosilylation of 1,4-bis(methyldihydrosilyl)benzene and methyldimethoxysilane with (terminal olefin-functionalized alkyl) substituted epoxides in the presence of platinum catalyst. 1,4-Bis[(glycidyl- or cyclohexene oxide-functionalized alkyl)methyl(hydroxy or methoxy)silyl]benzenes were obtained by hydrolysis and methanolysis of the hydrosilyl derivatives. Poly(silphenylenesiloxane)s with epoxy side groups were synthesized by hetero-polycondensation of the hydrosilane, hydroxysilane and methoxysilane functional groups in the prepolymer and 1,4-bis[(epoxy-functionalized alkyl)methylsilyl]benzene, or 1,1-dimethoxy(epoxy-functionalized alkyl)methylsilane in the presence of a catalyst. Tris(pentafluorophenyl)borane was found to be an excellent catalyst for the polymerization. Cross-linking a polymer with 1,4-diaminobenzene gave stretchable polymer film by solution cast method.