Effects of Phenyltriethoxysilane Concentration in Starting Solutions on Thermal Properties of Polyphenylsilsesquioxane Particles Prepared by a Two-Step Acid-Base Catalyzed Sol-Gel Process

Abstract

Spherical polyphenylsilsesquioxane particles were prepared by a two-step acid-base catalyzed sol-gel process, in which various amounts of ethanol were used as a solvent to vary the concentration of phenyltriethoxysilane (PhSi(OEt)₃) used as a starting alkoxide. The decrease in the PhSi(OEt)₃ concentration led to the decrease in the average molecular weight and glass transition temperature of the polyphenylsilsesquioxanes. Thus, the change of the PhSi(OEt)₃ concentration in the preparation of polyphenylsilsesquioxane particles by the two-step acid-base catalyzed sol-gel process is an effective means to control the glass transition temperature of the particles.