Suspension polymerization reaction engineering

Guerrero Sanchez Carlos, Erdmenger Tina, Sereda Petr, Wouters Daan, and Schubert Ulrich S. Water-soluble ionic liquids as novel stabilizers in suspension polymerization reactions Engineering polymer beads. Chem. Eur. J. 12 no. 35 (2006) 9036-9045. 

The suspension process is practiced by only a few companies because it offers a higher degree of production control and product engineering during polymerization step. This process suspends the water-based reactant in a hydrocarbon-based solvent. The net result is that the suspension polymerization creates the primary polymer particle in the reactor rather than mechanically in postreactions stages. Performance enhancements can also be during or just after the reaction stage. 

Description of suspension polymerizations fits most appropriately in Chapter 10, where polymer reaction engineering is the topic. This chapter focuses on dispersion and emulsion polymerizations. 

The reaction engineering aspects of these polymerizations are similar. Good heat transfer to a comparatively inviscid phase makes them suitable for vinyl addition polymerizations. Free-radical catalysis is mostly used, but cationic catalysis is used for nonaqueous dispersion polymerization (e.g., of isobutene). High conversions are generally possible, and the resulting polymer, either as a latex or as beads is directly suitable for some applications (e.g., paints, gel permeation chromatography beads, expanded polystyrene). Suspension polymerizations are run in the batch model. Continuous emulsion polymerization is common. 

The production of polyolefins by means of coordination polymerization, which is the highest tonnage polymerization process, is discussed first. The following chapters present the production of polymers by free-radical polymerization in homogeneous, heterogeneous and dispersed (suspension and emulsion) media. Afterwards, the reaction engineering of step-growth polymerization is discussed. The last chapter is devoted to the control of polymerization reactors. 

C. Kotoulas, C. Kiparissides, Suspension polymerization, in J. Asua (Ed.), Polymer Reaction Engineering, Blackwell Publishing Ltd, 2008, pp. 209-232. 

Emulsions, suspensions, and dispersions are examples of colloidal systems. It is important to mention that these terms are not always used consistently in the literature and that this situation may be confusing for students and nonpolymer scientists [24]. From the point of view of polymer science and engineering, these terms refer to heterogeneous polymerizations, particularly polymerizations in aqueous/alcoholic dispersed media. Thus, the aforementioned terms have connotations that have to do with the initiator, monomer, and polymer solubility in each phase as well as with particle size and the main locus of polymerization. These aspects are treated in detail later for the moment, let us assume that there are no chemical reactions and that such terms are used in the context of colloid science. 

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