1970 Volume 27 Issue 304 Pages 554-561
In the emulsion polymerization of methyl methacrylate (MMA) initiated by monomer peroxide of MMA in the presence of polymethacrylic acid (PMAA), the behavior of PMAA as an emulsifier was mainly studied in comparison with sodium lauryl sulfate (SLS). The results obtained were as follows. The initial rate of polymerization depended on the concentration of PMAA to the 0.4 power. Moreover, the rate of polymerization decreased at about 30% conversion, at which the monomer droplets disappeared. At the same time, many small particles (100-500A) were formed and the number of particles increased. These facts led to the same results as with SLS, wheras PMAA solubilized monomer to water (0.03-0.08%) and stabilized the emulsion particles. The particle sige distribution of emulsion in the presence of PMAA was rather broader than the emulsion with SLS.
From these results, it is most reasonable to conclude that the behavior of PMAA as an emulsifier is almost the same as SLS, excepting that the ability of stabilization of emulsion particles is slightly inferior to SLS, and that the mechanism of polymerization is almost the same as SLS.
