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Bubble‐free devolatilization in counterrotating nonintermeshing twin‐screw extruder
Author(s) -
Foster R. W.,
Lindt J. T.
Publication year - 1990
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760300707
Subject(s) - mass transfer , materials science , bubble , plastics extrusion , polystyrene , mechanics , barrel (horology) , penetration (warfare) , diffusion , composite material , polymer , thermodynamics , physics , mathematics , operations research
A theoretical analysis of the diffusion‐controlled, essentially bubble‐free, mass transfer regime of polymer solution devolatilization has been performed for a counterrotating, nonintermeshing twin‐screw extruder (1). The commonly used penetration diffusion approach is applied specifically to this geometry. Mass transfer from the recirculating pool and barrel film in the closed channel and the pool only in the open channel is taken into account. Use is made in this study of the recently determined pumping characteristics of this geometry (2), which allow the estimation of the length of the extraction section. Mass transfer rate measurements have been taken on a 20‐mm extruder using the model system polystyrene/ethylbenzene. The agreement between the mass transfer calculations and the experimental results is very good.