Emulsion polymerization is one of the most important commercial processes for converting unsaturated monomers into synthetic polymers. Billions of pounds of latex are produced annually for a broad range of applications such as: surface coatings, synthetic elastomers, adhesions, binders for non- woven materials, high-impact plastics, additives for construction materials and fluid property modifiers. Small volumes of latex products are also used in biomedical and scientific applications. Conventional emulsion polymerization involves the dispersion of a hydrophobic monomer, or monomers, into water with an oil-in-water emulsifier, followed by polymerization with a water-soluble initiator. Although the droplets in the monomer emulsion are usually 2 to 10 m, the diameters of the polymer particles in the final product are almost always in the submicron range. Hence, the reaction includes particle nucleation rather than simply polymerization in the monomer droplets. These systems exhibit characteristically high reaction rates and a high degree of polymerization. The product is comprised of colloidal polymer particles in a stable suspense, referred to as a latex dispersed in the aqueous phase. Dispersion polymerization is a process in which the continuous phase us a solvent for the monomers but not the resulting polymer formed is generally stabilized by block or graft copolymers. Resultant polymer particle size is many microns in diameter-the lower end of the suspension polymerization range. This research is aimed at obtaining a better knowledge of the reactions in the separate phases in heterogenous free radical polymerization systems. The main thrust is to examine the impact of reactions in the continuous phase when monomers with different solubilities are polymerized and when polymeric stabilizers are used with conventional monomers. Work in emulsion and dispersion polymerization will be done. The research will consist of both experimental and theoretical work. The experimental work will involve measurement of reaction rates, reagent concentrations, particle size distributions, copolymer compositional parameters and molecular weights. Model simulations will be used to evaluate the data and to extrapolate to new operating conditions. The results will be used to help custom design new molecules and products for specific high-value applications. The increased understanding of continuous-phase phenomena will also lead to improvements in existing products and processes.*** //
