Semibatch emulsion polymerization of butyl acrylate stabilized by a polymerizable surfactant

Abstract

In the semibatch emulsion polymerization of butyl acrylate (BA), the polymerizable surfactant, sodium dodecyl allyl sulfosuccinate (JS-2), increases the particle surface charge density significantly and, thereby, reduces particle size (as small as 90nm) of the latex product. Such a small particle size has not been achieved by means of the surfactant-free technique (normally greater than 300nm). The concentration of JS-2 in the initial reactor charge ([JS-2]i) is the most important parameter in determining the final latex particle size (dp). The number of latex particles formed is proportional to [JS-2]i to the 0.72 0.80 power. The experimental data also show that JS-2 should play a similar role in particle nucleation and growth to the conventional surfactant sodium dodecyl sulfate. The saturated particle surface area occupied by one molecule of JS-2 is 0.36 nm2 for the latex prepared by the surfactant-free technique. Furthermore, the saturated particle surface area covered by one molecule of JS-2 increases with particle surface polarity for the JS-2 stabilized latices. The fraction of the chemically incorporated JS-2 buried inside the particles increases with dp.