Seeded emulsion polymerization of styrene: Incorporation of acrylic acid in latex products

Seeded batch emulsion polymerization of styrene and acrylic acid was studie d. The influence of pH and acrylic acid content on the polymerization rate and the amount of carboxylic acid groups incorporated in the final latex pr oducts was investigated. The distribution of the functional groups over the aqueous phase, the latex particle surface, and the interior of the latex p article was determined using aqueous conductometric titration and nonaqueou s potentiometric titration at intermediate and complete overall conversions . Combined with kinetic results, the carboxylic acid group distribution his tory provided valuable information about the process of incorporation of ac rylic acid in latex products. Two-step processes in which a shot of acrylic acid was performed in the last stage of the emulsion polymerization reacti on were investigated as a strategy to increase the surface incorporation ef ficiency. (C) 2000 John Wiley & Sons, Inc.