INFLUENCE OF DISPROPORTIONATED ROSIN ACID SOAP ON THE EMULSION POLYMERIZATION KINETICS OF STYRENE

The effect of disproportionated rosin acid soap (DRAS) on the emulsion polymerization kinetics of styrene has been studied. Batch experiment s reveal a significant influence of chain transfer and limited particl e coagulation on the polymerization process. For the recipes studied, the number of growing chains in the emulsion and consequently the poly merization rate were found to be independent of the particle number du ring the interval of coagulation. However, for relatively large partic les (d(p) approximate to 100 nm), the polymerization rate was proporti onal to the particle number, indicating Smith-Ewart case II kinetics. These effects have been shown to be well predicted by model calculatio ns using a radical population balance over the particles. Since DRAS i s derived from naturally occurring constituents found in pine trees, i ts performance, and with that the properties of the product latex, may vary significantly. However, if the performance of DRAS is known, the recipe and process conditions can be optimized. For this reason a pro cedure has been developed to quantify the performance of DRAS from the simple batch experiments discussed in this paper, the polymerization kinetics, and the information obtained about the coagulation process. (C) 1995 John Wiley and Sons, Inc.