ABSTRACT
This chapter examines the technical requirements of the process—limitations and enhancement mechanisms for separation—prior to reviewing the available equipment. It discusses a few broad criteria for the selection of the equipment. Devolatilization of molten polymers is a thermodynamically driven, mass-transfer-limited separation process. Effective means of transferring heat to and from the polymer solution are essential while carrying out devolatilization. Devolatilization is sometimes used to enhance chemical reactions such as polycondensation or grafting. Intentional addition of a devolatilizing aid to the polymer is another practical approach available to the processor for improving separation efficiency, especially during the final stages of vacuum devolatilization. Vapors removed from the devolatilizer are condensed quickly, both to reduce the load on the vacuum system and to recover most of the volatiles back into a process stream.
