Morphological characteristics of poly(styrene-co-divinylbenzene) microparticles synthesized by suspension polymerization

The synthesis of poly(styrene-co-divinylbenzene) microparticles by the suspension polymerization technique requires the use of some protective agents to reduce the coalescence/agglomeration of the microparticles during the polymerization process. Since the effect of each protective agent may vary, depending on the type and proportion of the other reactants in the polymerization mixture, the influence of certain factors affecting the protective properties of tricalcium phosphate on the mean particle size, the particle size distribution, and the agglomeration of microparticles was studied using the design of experiments methodology. The factors investigated were the ammonium hydroxide and surfactant concentrations and impeller off-bottom clearance. The models thus obtained indicate that the absence of NH4OH in the polymerization mixture, or a low level of the surfactant agent, leads to agglomeration of the microparticles. It was also observed that a low value of the impeller off-bottom clearance factor and a high value of the sodium dodecyl sulfate (SDS) concentration favor the formation of microparticles with a narrower particle size distribution. Additionally, microparticles with the smallest mean size were obtained using the highest value of the impeller off-bottom clearance factor.