The Effect of Alcohol Precipitants on Structural and Morphological Features and Thermal Properties of Lyocell Fibers

Makarov, I.S.; Golova, L.K.; Vinogradov, M.I.; Levin, I.S.; Shandryuk, G.A.; Arkharova, N.A.; Golubev, Y.V.; Berkovich, A.K.; Eremin, T.V.; Obraztsova, E.D.

Авторы: Makarov I.S., Golova L.K., Vinogradov M.I., Levin I.S., Shandryuk G.A., Arkharova N.A., Golubev Y.V., Berkovich A.K., Eremin T.V., Obraztsova E.D.
Журнал: Fibers
Том: 8
Номер: 6
Год издания: 2020
Номер статьи: 43
DOI: 10.3390/fib8060043
Аннотация: This research examines the possibilities of regulating the structure of cellulose precursorfibers spun from solutions in N-methylmorpholine-N-oxide when replacing aqueous coagulationbaths with thermodynamically softer alcohol baths at different temperatures. The fibers were spunby the dry jet–wet method in isobutanol coagulation baths with a temperature of 25 °C and 70 °C.The study of the phase state of the solvent–coagulant system using viscometry and point cloudmethods revealed the temperature-concentration regions of the single-phase and two-phase statesof the system. Using elemental analysis, DSC (differential scanning calorimetry) and XRD (X-raydiffraction) methods, it was shown that just spun fibers, due to the presence of a residual amountof solvent and coagulant in them, regardless of the temperature of the precipitator, have anamorphous structure. Additional washing with water completely washed away the solvent andcoagulant as well, however, the structure of cellulose changes slightly, turning into a defectiveamorphous-crystalline one. A relationship was found between the phase composition, structure,and properties of just spun fibers and precursors washed with water. Thus, the loss of structuralordering of both just spun and washed cellulose fibers leads to a decrease in strength characteristicsand an increase in deformation. The thermal behavior of the fibers is determined by their phasecomposition. Fibers just spun into hot alcohol containing a coagulant and traces of solvent acquirethermal stability up to 330 °C. During the pyrolysis of the obtained precursors up to 1000 °C, thevalue of the carbon yield doubles. The amorphized structure of the obtained fibers allows us toconsider it as a model when analyzing the transformation of the structure of precursors duringthermolysis.
Добавил в систему: Левин Иван Сергеевич

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The Effect of Alcohol Precipitants on Structural and Morphological Features and Thermal Properties of Lyocell Fibersстатья

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