STUDY OF PARTICLE NUCLEATION, FLOCCULATION, AND GROWTH IN THE EMULSIFIER-FREE POLYMERIZATION OF STYRENE IN WATER BY TOTAL INTENSITY LIGHT-SCATTERING AND PHOTON CORRELATION SPECTROSCOPY

A comparison has been made between stirred and unstirred reactions for the polymerization of styrene in water, in the absence of surfactant, using a free radical anion initiator (potassium persulfate). Unstirred reactions were probed with total intensity light scattering and photon correlation spectroscopy, thereby enabling an in situ sizing of the growing latex particles. Transmission electron microscopy was carried out on latices prepared in both types of reactions. It is concluded that particle growth by imbibition and polymerization of styrene monomer causes particle destabilization, which is followed by flocculation and coalescence. These processes are important factors contributing to the growth and the monodisperse nature of latices prepared in both stirred and unstirred reactions. The presence of aggregates at the end of such reactions is a natural consequence of the extensive flocculation (number density falls by factor of 103 to 105) which occurs and agrees with recent experimental findings from stirred reactions. © 1979.