THE STABILIZATION EFFECT OF MIXED-SURFACTANTS IN THE EMULSION POLYMERIZATION OF METHYL-METHACRYLATE

The emulsion polymerization of methyl methacrylate (MMA) was conducted at 50°C using either anionic or nonionic surfactants, or a mixture of the two at different surfactant concentrations. In the singlesurfactant systems a proportional relationship was observed between the total particle surface area per cm3 of aqueous solution at 90% conversion (TS) and the amount of surfactant used. For mixed-surfactant systems, a relationship close to an additive one was found between the TS value and the amount of each surfactant used. The particle number did not remain constant during the polymerization, while the TS value continuously increased. It was also found that MMA formed a paste easily at higher (M/W) ratios, which could be alleviated by using higher surfactant concentrations. © 1990 Springer-Verlag.