Preparation of polyaryloxysilanes and polyaryloxysiloxanes by B(C6F5)3 catalyzed polyetherification of dihydrosilanes and bis-phenols

Polyaryloxysilanes and siloxanes (PAS) are an interesting and useful class of polymers with excellent flammability characteristics. The B(C6F5)(3) catalyzed dehydrocondensation of bis-phenols or their simple alkylethers with dihydrosilanes and siloxanes provides ready access to these polymers. The reaction proceeds readily even when hindered phenol or silane substrates are employed affording sterically protected PAS derivatives. The combination of steric hindrance around the silyl ether linkage, the absence of ionic impurities and the use of very low levels of the boron catalyst in these reactions produces thermally and hydrolytically robust materials, which should further enhance their utility. Phenol functional macromonomers, such as polycarbonate and PPO derivatives, are readily coupled, providing easy access to siloxane copolymers. The only severe limitation of this process for preparing PAS derivatives is that the reaction is intolerant of base functionality in either the monomers or solvents used in the reactions.