Polymerization in gel‐like emulsions

Abstract

Abstract Polymerization of styrene in gel‐like emulsions (concentrated emulsions which have a volume fraction of monomer greater than 0.74), by using sodium dodecylsulfate as emulsifier and small amounts of water, was carried out with an oil‐soluble initiator, AIBN. Both higher conversions and higher molecular weights of the polymer were obtained as compared to the polymerization in bulk. The higher “rigidity” of the monomer in the interior of the cells of the gel is responsible for the increased rate of polymerization and molecular weight. The polymer particles thus obtained have diameters in the range of 0.1 to 0.3 μm, depending upon the conditions of preparation of the gel. The effects of the concentration of the initiator, the concentration of surfactant, the monomer volume fraction, termperature, and ionic strength of the aqueous solution have been investigated.