writer：吕玉霞, 李小艳, 米勤勇, 王德修, 余坚,* 张军*
keywords：纤维素, AmimCl 离子液体, 气凝胶, 超临界CO2, 凝固浴
source：期刊
specific source：中国科学: 化学, 2011, 41(8): 1331-1337.
Issue time：2011年

利用离子液体AmimCl 溶解结合超临界CO2 干燥的方法制备了纤维素气凝胶材料.研究了不同初始浓度的纤维素溶液及其在不同凝固浴中制备的纤维素凝胶的流变行为, 进一步考察了纤维素溶液浓度和凝固浴种类对纤维素气凝胶材料结构的影响. 结果表明, 随着初始纤维素溶液浓度的增大, 气凝胶的孔结构逐渐致密, 比表面积随之减小; 凝固浴的组成对纤维素气凝胶的结构也有较大影响. 采用适当的制备条件, 可以制备出高比表面积的纤维素气凝胶材料. 对纤维素气凝胶的热性能进行了表征, 结果表明所得到的气凝胶材料具有较好的热稳定性和较高的炭残余含量.

Cellulose aerogel materials were prepared by combining dissolving cellulose in an ionic liquid, 1-allyl-3-methylimidazolium chloride (AmimCl), and drying in supercritical CO2. The rheological properties of the cellulose solutions of different concentrations and their gels regenerated in different coagulation baths were studied. The porous structure and morphology of cellulose aerogels were found to be affected by cellulose concentration and nature of the coagulation bath. With increasing initial cellulose concentration, the porous structure of cellulose aerogels became more dense and uniform, leading to the gradual decrease of the specific surface area. Further, it was also observed that, both viscosity and the polarity of coagulation bath affected the structure of cellulose aerogels. High specific surface areacellulose aerogel materials could be prepared by controlling the experimental conditions. The obtained cellulose aerogels had relatively high char yield at elevated temperature, which makes them potential precursors for fabrication of novel mesoporous carbon materials.