Polymers containing alternating silsesquioxane and bridging group segments and process for their preparation

摘要

A synthesis process for polysilsesquioxanes which produces a high yield, tractable copolymer of perfectly alternating silsesquioxane and bridging group segments is provided. A difunctional silsesquioxane monomer of the formula Si8R8O11(OA)2 or Si7R7O9(OSiR4R5R6) (OA)2 is reacted with a difunctional compound of the formula X-M-X which forms a bridging group for a time sufficient to condense the difunctional silsesquioxane monomers and bridging groups into a linear polymer containing alternating silsesquioxane and bridging group segments. The resulting linear copolymer is essentially free of impurities and has controllable properties through the proper selection of the monomeric starting materials.