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Title
Dissolved state and viscosity properties of cellulose in a NaOH complex solvent
Authors
Shuai Zhang Fa-Xue Li Jian-Yong Yu and Gu Li-Xia
Received
June 20, 2008
Published
Volume 43 Issue 7-8 July-August
Keywords
cellulose dissolution, NaOH complex, low temperature, viscosity
Abstract
Cellulose may be quickly dissolved in a NaOH complex solvent (NaOH/urea/thiourea/H O). A detailed 2 investigation on the effects of solvent composition and temperature on cellulose solubility has been presented. Optical microscopy and wide-angle X-ray diffraction (WAXD) were used to study the process of dissolution. The highest solubility of cellulose was recorded in NaOH/urea/thiourea/H O with an 8/8/6.5/77.5 2 composition, at –10 °C, although the components of this solvent cannot dissolve cellulose on their own, even at a low temperature. CP MAS 13C NMR spectra proved that, during regeneration, cellulose I (cotton linters) first changed to amorphous cellulose chains in solution and then to cellulose II. The intrinsic viscosity [?] of the cellulose solutions revealed that the cellulose complex occurs as flexible coil chains in the NaOH/urea/thiourea aqueous system, the chain stiffness of cellulose being higher than that of normal synthetic polymers, in a good solvent. According to relative viscosity measurements, the cellulose solution was stable during the storage stage.
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