Morphological Transformations in the Process of Coagulation of Cellulose Solution in N-Methylmorpholine N-Oxide with Isobutanol

Evolution of the morphology of cellulose solutions in N -methylmorpholine- N -oxide during coagulation with a “soft” coagulant, isobutyl alcohol, at different temperatures is considered. Using optical interferometry and transmitted and scanning electron microscopy the mechanism of phase separation o...

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Bibliographic Details
Published in:Polymer science. Series C 2021-09, Vol.63 (2), p.161-169
Main Authors: Makarov, I. S., Golova, L. K., Vinogradov, M. I., Mironova, M. V., Arkharova, N. A., Klechkovskaya, V. V., Kulichikhin, V. G.
Format: Article
Language:English
Subjects:
Alcohol
Cellulose
Chemistry
Chemistry and Materials Science
Coagulants
Coagulation
High temperature
Isobutanol
Microreactors
Morphology
Phase separation
Polymer Sciences
Polymers
Reviews
Room temperature
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Summary:Evolution of the morphology of cellulose solutions in N -methylmorpholine- N -oxide during coagulation with a “soft” coagulant, isobutyl alcohol, at different temperatures is considered. Using optical interferometry and transmitted and scanning electron microscopy the mechanism of phase separation of the system to form a polymer phase is studied depending on the temperature of alcohol. It is shown that, in the case of a room temperature coagulant, a heterogeneous film with a droplet texture enlarging over thickness appears along the precipitation front. At a high temperature of alcohol the coagulation of the solution occurs in two stages. At the first stage the penetration of the coagulant into the jet of spinning solution leading to the formation of vacuoles occurs. The phase separation of the solution proceeds within the vacuoles as microreactors to form a polymer-concentrated shell and a polymer-diluted phase in the vacuole cavity. At the second stage the coagulant diffuses through the vacuole shell into the bulk of the solution and causes its uniform coagulation. The process of vacuole formation is visualized. The transverse cleavage of the film is analyzed by energy dispersive X-ray spectroscopy. The difference in the content of C, N, and O atoms on the walls of vacuoles and in the region of a film with a uniform cellular morphology is established.
ISSN:1811-2382
1555-614X
DOI:10.1134/S181123822102003X