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Polymer melt devolatilization mechanisms
Author(s) -
Albalak Ramon J.,
Tadmor Zehev,
Talmon Yeshayahu
Publication year - 1990
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690360904
Subject(s) - polymer , polystyrene , materials science , scanning electron microscope , core (optical fiber) , polyethylene , composite material , superheating , bubble , low density polyethylene , chemical engineering , physics , parallel computing , computer science , engineering , condensed matter physics
Scanning electron microscopy (SEM) was used to study the mechanism of falling‐strand devolatilization of polymer melts. Polystyrene and low‐density polyethylene were enriched with styrene and hexane, respectively, and were subsequently extruded as thin strands at various conditions. The polymer strands were exposed to superheat conditions for preset periods of time ranging from tenths to tens of seconds. The strands were then frozen, fractured, and studied by SEM. Devolatilization was found to proceed through a blistering mechanism, both on the surface of the strands and on the surfaces of volatile bubbles formed within the core of the melt. At all volatile concentrations surface blistering and foaming preceded bubble growth in the core, and occurred before the strands foamed. A mechanism for the observed polymer melt devolatilization is proposed.