Influence of Semi-Batch Operations on Morphological Properties of Polystyrene Made in Suspension Polymerization

Abstract

Abstract Suspension polymerization reactions in industrial processes are usually carried out with batch operations. However, discontinuous systems do not offer process flexibility like semi-continuous ones. Studies and practical applications of semi-batch operations in heterogeneous systems are commonly found for emulsion polymerization systems in order to control copolymer composition, molecular weight, final particle size, particle morphology and reaction rate. On the other hand, semi-batch operations are rarely used to carry out suspension polymerizations. In these systems, this sort of operation strategy can be applied for the production of core-shell particles. The present study intends to show that semi-batch operation can also be used in suspension polymerization systems to manipulate and improve some morphological properties of the produced particles. The styrene suspension polymerization was used as case study. The reactions were carried out considering different monomer feeding rates and reaction times at which the monomer feed stream begins to be added to the system. Results showed that, depending on the semi-batch strategy adopted ( i.e. reaction time for the beginning of the organic phase feed and feeding rate), it is possible to successfully control some morphological properties of the particles, leading to the production of more uniform particles sizes than those ones obtained in classical suspension systems.