Multiple Injection Method for Bulk Syndiospecific Polymerization of Styrene with Homogeneous Metallocene Catalyst

Abstract

At the early stage of a bulk syndiotactic polymerization of styrene, the homogeneous reactant mixture transforms to a slurry state consisting of a precipitated solid syndiotactic PS and a liquid reactant mixture. As the reaction proceeds, the slurry transforms into a wet and then a dried powder if proper methods are used to prevent agglomeration. When a large amount of catalyst and co-catalyst is added to the styrene to achieve a high conversion rate, the reactant mixture becomes a lumpy agglomeration and further control of the reaction is impossible. In this study, we introduce a novel approach to avoid such agglomeration while maintaining a high conversion rate. Instead of adding the catalyst and co-catalyst at once, the total amount of the catalyst and co-catalyst is divided into several parts and added successively. This method is found to be very effective to avoid the formation of agglomerate and to maintain a fairly high conversion rate of slurry into powdery product (up to 70 %). It is also observed that this method produces syndiotactic PS of a higher molecular weigh. 요 약