Savchenko M. Obtaining of a superfine silicon dioxide modified by urea-formaldehyde polymeric compounds

The subject of the thesis is developing the technology of obtaining high-dispersity silicon dsoxide modified by urea- formaldehyde polymeric compounds from water glass solution. The technique evolved allows obtaining the modified silicon dioxide wich pre-assigned physical and chemical properties wich the purpose of using it in rubber industries. Thermodynamic study of the equilibrium composition of Si-O-H-Na-S water solution was carried out taking the solid phase formation into consideration. The temperature conditions of the process have been studied. The necessity of a two-staded procedure has been proved experimentally. The conditions for silicon dioxide sol stability have been found. Turbidimetric method was used to study the kinetics of silicon acids polycondensation in sodium silicate solutions. The order of the reversible polycondensation reaction, it rate and equilibrium constants have been determined. The dependence and process conditions has been investigated. The impact of the process parameters on physical and chemical properties of the product obtained has been studied. The optimum propottions of organic versus inorganic partions proved to be 20/80. The basic flow diagram for obtaining the superfine silicon dioxide modified by urea-formaldehyde polymeric compounds has been developed.