Aspects of the emulsifier-free emulsion polymerization of styrene

This thesis presents the results of a study on various aspects of the emulsifier-free emulsion polymerization of styrene.;Increasing the ionic strength decreased the zeta potential but most latexes measured were found to be at least moderately stable. All three latexes demonstrated an anomalous maximum in the zeta potential - negative log specific conductance curve. As well, all three latexes demonstrated a dependance of zeta potential on pH. Zeta potential increased with increasing pH. Electrokinetic values for the surface charge density were comparable to values of surface charge density obtained from conductometric titrations. It is recommended that electrokinetic measurements be used in correlational experiments only where there is a high degree of uniformity.;The mechanism of particle formation was studied using pillared hydrotalcites. It was hypothesized that a knowledge of the nature of the initial polymer phase may distinguish between in situ micellization and homogeneous nucleation mechanisms of particle formation. It was found that the initial polymer phase is oligomeric in nature which is likely to associate to form micelles in situ. (Abstract shortened by UMI.).;It was found that increasing the initiator concentration increased the number average particle diameter and the polydispersity. The ionic strength of the aqueous phase increases with increasing initiator concentration which may explain the increasing trend in particle diameter. The effect of ionic strength dominates the particle size determining mechanism in the range of initiator concentrations studied. It was also found that at a constant initiator concentration, increasing the ionic strength of the aqueous phase increased the number average particle diameter. At constant ionic strength, the particle size decreased with increasing initiator concentration.