Preparation of high cleanliness submicron polysilsesquioxane microspheres

The submicron sized polysilsesquio-xane microspheres were synthesized by hydrolysis and polycondensation two-step method using methyltri-methoxysilane as reaction monomer in deionized water solution. The effects of conductivity of deionized water and pH value of monomer on hydrolysis time, polymerization time, and particle size of microsphere were investigated, as well as the effect of chloride ion content in monomer on surface cleanliness of microspheres. The morphology, particle size distribution, organic functional groups and thermal properties of the microspheres were analyzed and characterized by scanning electron microscopy, particle size distribution testing, Fourier transform infrared spectroscopy and thermogravimetric analysis. The results showed that under the conditions of deionized water conductivity less than 15 μS/cm, pH value of monomer 4-5 and chloride ion content in monomer less than 0.023 mg/L, it was favorable for preparation of submicron polysilsesquioxane microspheres with high level cleanliness .