REACTIVE SURFACTANTS IN HETEROPHASE POLYMERIZATION .4. DISPERSION POLYMERIZATION OF STYRENE AND METHYL-METHACRYLATE - PARTICLE FORMATION AND PREDICTION OF FINAL SIZE

The mechanism for the formation of polymer particles in the dispersion polymerization of methyl methacrylate and styrene in alcohol-water mi xtures has been investigated. Methacrylic based poly(ethylene oxide) m acromonomers and poly(vinyl-pyrrolidone) have been used as steric stab ilizers. Dynamic light scattering as well as transmission electron mic roscopy have been applied to determine the evolution of the average pa rticle size at the beginning of the polymerization. Stable nuclei from 80 to 400 nm in diameter size were detected. The nucleation process w as quite rapid and completed within less than cn. 0.1% monomer convers ion. The experimental results are compared with those predicted by the multibin kinetics model for coalescence developed by Paine [(1990) Ma cromolecules 23: 3109].