New Insights on surfactant-free styrene emulsion polymerization in The presence of sodium styrene sulfonate

The surfactant-free styrene emulsion polymerization (EP) in the presence of sodium styrene sulfonate (NaSS) was experimentally studied. It was observed that as the NaSS content is higher the number of particles (N) and the breath of the particle size distributions increases. Although EP's were performed without added surfactant, the N values obtained in these cases reach values typical of EP's performed in the presence of micelles. These experimental findings are explained in terms of the role of the oligomers formed in the aqueous phase and the feasibility that in situ micellization and micellar nucleation were occurring in these systems is also discussed. The hypothesis proposed in this work contrasts with the ones reported in the literature.