林业工程学报2017，Vol.2Issue(1)：103-107,5.DOI:10.13360/j.issn.2096-1359.2017.01.018
叔丁醇冷冻干燥法制备纳米纤维素气凝胶
Fabrication of nano-cellulose aerogels by freeze drying using tert-butyl alcohol as displacement solvent
摘要
Abstract
Highly porous nano⁃cellulose aerogels were prepared through a spontaneous physical gelation route by using calcium chloride solution in combination with tert⁃butyl alcohol solvent displacement and freeze drying technology. According to colloidal stability theory, the existence of calcium chloride could change the original charge distribution of the sol system to improve the gel formation process of the nano particles. Replacing water with tert⁃butyl alcohol could reduce capillary force, thus reducing the damage to the gel network structure during the drying process as well as lowering the shrinkage rate of aerogel to maintain its three dimensional network structure. The microstructure, spe⁃cific surface area, pore size distribution, and thermal degradation of resulting aerogel were characterized with scanning electron microscope, micrometrics analyzer and thermo gravietric analyzer, respectively. The prepared nano⁃cellulose aerogels were white solid and the shrinkage of nano⁃cellulose aerogels were neglectable. Nano⁃cellulose aerogel of 3�5% mass ratio exhibited the highest specific surface area up to 174�3 m2/g, and an average pore size of 18�4 nm and weak shrinkage of 7�86%. The isotherm adsorption⁃desorption curves of nano⁃cellulose aerogels were of Type II ( IUPAC classification) . The distribution of pore size indicated the meso and macro pores, which was consistent with the results from nitrogen physisorption isotherms. The pore volume, specific surface and the porosity of nano⁃cellulose aerogels increased while the shrinkage decreased with the increasing cellulose mass ratio. Nano⁃cellulose aerogel showed a similar thermal degradation behavior as MCC(microcrystalline cellulose) and NCC(nanocrystalline cellu⁃lose) , while the onset degradation temperature of aerogel was lower than those of MCC and NCC.关键词
纳米纤维素/气凝胶/叔丁醇/氯化钙/冷冻干燥Key words
nanocellulose/aerogel/tert-butyl alcohol/calcium chloride/freeze drying分类
化学化工引用本文复制引用
王晓宇,张洋,江华,宋宇轩,周兆兵,赵华..叔丁醇冷冻干燥法制备纳米纤维素气凝胶[J].林业工程学报,2017,2(1):103-107,5.基金项目
国家林业公益性行业科研专项（201504603）；南京林业大学优秀博士学位论文创新基金项目基金（163020772）。 （）
