Dissolution of cellulose into supercritical water and its dissolving state followed by structure formation from the solution system.

Carbohydr Polym

Faculty of Home Economics, Kobe Women's University, 2-1 Aoyama, Higashisuma Suma-ku, Kobe 654-8585, Japan. Electronic address:

Published: January 2022


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Article Abstract

Cellulose was treated with supercritical water at 668 K and 25 MPa for 0.04 s in this study. The cellulose/water system was transparent at room temperature for a while after supercritical water treatment before a precipitate gradually appeared over several hours. The precipitation process was monitored by synchrotron X-ray scattering. The scattering functions of fractal systems and flat-like structures were utilized to explain the experimentally observed small-angle scattering profiles. Immediately after supercritical water treatment, the cellulose appeared to dissolve with a fractal dimension D of approximately 1, indicating that the cellulose molecules were rigid, followed by aggregation into a 5-nm-thick flat-like structure. The flat-like structure was determined to be similar to the molecular sheets observed during the early stages of precipitation in the cellulose/aqueous sodium hydroxide and cellulose/aqueous lithium hydroxide/urea systems. Resultant regenerated cellulose had high crystallinity, large crystal size, and a low degree of polymerization.

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http://dx.doi.org/10.1016/j.carbpol.2021.118669DOI Listing

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