Cellulose dissolution in aqueous lithium bromide solutions
A new all-aqueous process of the dissolution/regeneration of cellulose was developed. Cellulose was completely dissolved in the 54–60 wt% lithium bromide aqueous solutions in the temperature range of 110–130 °C within a dissolution time of 1 h. Then, the cellulose was directly regenerated from the solution by cooling down to approximately 70 °C and removing the salts with water, yielding a translucent gel. The cellulose gel was not significantly chemically decomposed even though some decrease of the degree of polymerization occurred during the dissolution/regeneration of cellulose. The X-ray diffraction analysis demonstrated that the dissolution/regeneration of cellulose induced a crystalline structural change from cellulose I to cellulose II, confirming the complete loss of the original cellulose structure. The cellulose gel had highly porous three-dimensional networks composed of fairly long cellulose fibrils interconnected with one another. The dissolution/regeneration of cellulose in aqueous lithium bromide solutions offers new and important options for cellulose-based materials.
KeywordsCellulose Cellulose solvent Lithium bromide Hydrogel
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF-2012R1A1A2042532) and a grant from the Kyung Hee University in 2011 (KHU-20110470). Also, this study was carried out with the support of Forest Science & Technology Projets (Project No. S211313L010110) provided by Korea Forest Service.
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