Ultrasonically irradiated emulsion polymerization of styrene in the presence of a polymeric surfactant

A polymeric surfactant based on carboxymethyl cellulose and alkyl poly(etheroxy) acrylate (CMC‐A9) was used in ultrasonically irradiated emulsion polymerization of styrene. Polystyrene nanoparticles (30–60 nm) with high molecular weight were prepared. Compared with the conventional emulsion polymerization, the introduction of CMC‐A9 in the polymerization yielded higher monomer conversion in a shorter time and under lower ultrasonic power output. A single latex particle contained only a few polymer chains with average chain numbers of 2–19. The particle size and polymer chain per particle could be controlled by changing the concentration of CMC‐A9 and SDS. The effect of CMC‐A9 and SDS on ultrasonically irradiated emulsion polymerization kinetics was studied. The results indicated that the ultrasonically irradiated emulsion polymerization had a similar nucleation mechanism to a miniemulsion polymerization system. This is attributed to the high ratio of radicals and a great number of smaller sizes of monomer droplets produced under ultrasonic irradiation.