Polymerization reactors particulate products

In this chapter we deal with the entire journey of polymeric particulate solids, from the polymerization reactor to the shaped and structured finished product. The reader is referred to Chapter 1, which discusses all the processes and elementary steps involved in this journey. 

Pickering stabilizers, commonly used in styrene suspension polymerization, are inorganic solids, insoluble in the aqueous phase. Their main advantage is that they can be removed easily from the final particulate product (e.g., by dilute acid), which improves the clarity and transparency of the polymer. Also, the amount of polymer deposited on the wall and on other parts of the reactor decreases, which considerably improves the heat transfer rate from the reaction medium to the coolant. Finally, it should be mentioned that inorganic powders are usually cheaper [5]. 

A very widespread issue in polymer production is the existence of nano-, micro-, and macroscopic particulates. In some cases, these particulates are integral to the process, such as bacteria in bioreactors, cell fragments in bioextraction, or latex particles in emulsion polymerization. In most cases, however, the particulates are unwanted and can be detrimental both to the product and the reactors. Such particulates include physical aggregates, branched and cross-linked microgels, microcrystals, impurity particles, and macroscopic coagula. This topic is covered in depth in Section 14.3. 

Dual function filtrodynamics, to both characterize the presence, onset, and evolution of particulates that occur in polymerization processes and protect instrumentation through which diluted polymer reactor solution flows (e.g., as in ACOMP), is currently under development. Challenges include delineating which types of filters work best with given particulate systems (e.g., microgels from natural product solutions, or from microgels occurring in polymerization reactions in emulsions and inverse emulsions, etc.)... 

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