Silsesquioxane polymers

Patent Granted Many polymeric forms of silsesquioxanes have been developed with varying molecular weights and synthesis methods. The first high molecular weight tractable polymeric silsesquioxane was a ladder type repeating unit, seen in Figure 3, polyphenylsilsequioxane, reported by Brown et al. in 1960.[9] Brown’s findings were used as a basis for further research and synthesis variations by plethora of additional research groups investigating polyphenylsilsequioxanes. Though many alterations were made, the origin synthesis proposed by Brown involved a three step process outlined as follows: (1) the hydrolysis of phenyltrichlorosilane in a solvent with excess water to give a hydrolyzate, (2) equilibration of the hydrolyzate with potassium hydroxide at a low concentration and temperature to give the prepolymer, and (3) equilibration of the prepolymer at a high concentration and temperature to give the final polymeric form.