Reactor design considerations for gas—liquid emulsion polymerizations: the ethylene—vinyl acetate example

Abstract

Gas—liquid emulsion polymerization presents certain problems which are not normally encountered during conventional emulsion polymerizations. The existence of a comonomer in the gas phase results in mass transfer limitations under cetain reaction conditions. Designed experiments have been used to study the ethylene-vinyl acetate emulsion process. These studies have identified the reaction conditions under which ethylene mass transfer limitations prevail. The present paper will focus on the results of a more detailed study of the reactor design itself. These results may be used to eliminate or reduce mass transfer limitations during ethylene-vinyl acetate emulsion polymerization. Results showing the effects of impeller design, sparging and agitation on the rate of polymerization, cumulative copolymer composition, particle size and number, and gel content are presented. As a result, one can identify the requirements, with respect to both reaction kinetics and reactor design, for the production of a high solids, homogeneous, high ethylene content copolymer. These observations, when coupled with the approach and the kinetic results presented earlier, provide a check-list of the requirements for successful scale-up of the process.