Devolatilization is the process by which unreacted monomer, solvent, water, dissolved gases, or other undesirable volatile contaminants are removed from a polymer melt or solution. It is a mass-transfer process driven a combination of thermodynamic and diffusional variables, with the design of the machine impacting both of these parameters. It is driven by superheating the volatile component, followed by exposing the melt or solution to a rapid decompression.
Single-screw or multi-screw extruders, or any number of custom or commercially available stripping devices such as wiped film evaporators, have been used for devolatilization. The choice is largely driven by the nature of the polymer to be stripped, the concentrations of volatiles, and other processing actions required for the product.
Despite the major commercial significance of devolatilization, little has been written on the topic.
- Why devolatilize? Isolation of cleaning operation
- Types of devolatilization equipment
- Twin-screw devolatilization techniques
- The "big three" process variables
Robert E. Jerman
Owner, Extrusion Technology and Innovations
Rob Jerman has developed twin-screw extrusion systems for devolatilization, mixing and compounding, and reactive systems for over 30 years and has significant experience in product and process development in fluoropolymers. He has his own consulting firm, Extrusion Technology and Innovations, part of Extrusion Edge.
Editorial Director, Plastics Technology
Jim has been in plastics journalism since 1988, when he joined the staff of Plastics World Magazine as senior editor. Jim joined Plastics Technology in 1997 as executive editor, and became editorial director in 2009. In addition to being responsible for the overall editorial strategy of the magazine, Jim enjoys reporting on extrusion technology.
Sponsored by: Brabender Instruments, Leistritz, Star Plastics, and VAC-U-MAX