SELECTION OF SUITABLE CATALYSTS FOR PRODUCTION OF NEW NANOCOMPOSITE MATERIALS

Abstract

The article is devoted to the principles of hydrolytic polycondensation of tetramethoxysilane (TMOS) in an alkaline environment. Monolithic samples of SiO2 particles and xerogels were synthesized as a result of hydrolytic polycondensation of tetramethoxysilane in alkaline medium. Amine catalysts - pyridine derivatives were used to carry out the process. As a result, samples of different sizes were synthesized depending on the concentration of substances taken as catalysts. Smaller diameter particles were obtained at lower amine concentrations and larger diameter particles at higher concentrations. As the pKa value of the catalysts used in the synthesis of xerogels increases, certain increases and decreases in the properties of the resulting particles have been observed. Thus, with an increase in the pKa value, the density and hardness of the samples decreased, the percentage of SiO2 increased, and at the same time, the gelation time in the sol-gel system decreased. Images of the synthesized particles were obtained using a scanning electron microscope (SEM). Keywords: sol-gel, hydrolysis, polycondensation, tetramethoxysilane, xerogel, pKa, catalyst, SEM.