Effect of the Stability of Highly Concentrated Emulsions Containing Styrene–Divinylbenzene Mixtures on the Structure of Highly Porous Copolymers Formed on Their Basis

Highly porous polymer materials with preset pore sizes and porosities can be prepared via polymerization of dispersion media of highly concentrated water-in-oil emulsions. In this work, the effect of divinylbenzene concentration in styrene–divinylbenzene mixed dispersion media of highly concentrated emulsions on the emulsion stability and the structure of resulting polymer materials has been investigated. It has been found that the emulsion stability at 25 and 65°C decreases with an increase in divinylbenzene concentration. Therewith, the pore size in the polymer material slightly grows from 4.0 to 4.5 μm. Emulsion stability expectedly rises with the concentration of a surfactant (Span 80). It has been shown that concentrations of divinylbenzene and Span 80 equal to 10 vol % are optimal for obtaining highly porous polymers from emulsions containing ammonium peroxodisulfate as a polymerization initiator. When emulsions containing benzoyl peroxide as a polymerization initiator are used to obtain highly porous polymers, NaCl (0.02–0.03 wt %) should be added to the dispersed phase of the emulsions. In this case, emulsion stability increases due to a decrease in the Ostwald ripening rate. Accordingly, highly porous polymers with smaller pores are obtained.