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›› 2013, Vol. 13 ›› Issue (2): 351-355.

• 材料工程专栏 • 上一篇    下一篇

无机盐诱导凝胶法制备纤维素气凝胶

魏志平 王涛   

  1. 清华大学化工系化学工程国家重点实验室 清华大学化工系
  • 收稿日期:2013-01-08 修回日期:2013-03-01 出版日期:2013-04-20 发布日期:2013-04-20
  • 通讯作者: 魏志平

Preparation of Cellulose Aerogel by the Salt-induced Gelation

WEI Zhi-ping WANG Tao   

  1. State Key Lab of Chemical Engineering, Department of Chemical Engineering, Tsinghua University Department of Chemical Engineering, Tsinghua University
  • Received:2013-01-08 Revised:2013-03-01 Online:2013-04-20 Published:2013-04-20
  • Contact: WEI Zhi-ping

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被引次数

10

摘要： 在纤维素-7% NaOH-12%尿素水溶液体系中加入少量无机盐诱导和促进体系形成凝胶，研究了不同种类和用量的无机盐对凝胶形成过程的促进作用，促进能力依次为：阴离子相同时，钾盐>钠盐>锂盐；阳离子相同时，氯盐>溴盐>硝酸盐. 无机盐浓度越高对凝胶形成的促进作用越明显. 在此基础上结合溶剂置换和超临界CO2干燥技术，提出了无机盐诱导凝胶法制备纤维素气凝胶的新工艺，用SEM、氮吸附仪和压汞仪对所制气凝胶材料进行了结构表征，材料具有介孔到大孔范围的多孔结构，介孔的比表面积为284 m2/g，孔体积为2.0 cm3/g，平均孔径为20.5 nm；大孔的孔体积为13.95 cm3/g，平均孔径为0.732 μm，孔隙率达91%.

关键词: 纤维素, 凝胶, 无机盐, 诱导, 气凝胶

Abstract: For the cellulose-7% NaOH-12% urea aqueous solution, adding inorganic salts can induce and accelerate its gelation process. The inorganic salts show a remarkable accelerating effect on the gelation with the sequences as K+>Na+>Li+ for cations and Cl->Br->NO3- for anions. For all kinds of salts used, the gelation rate increases with the increase of the salt dosage. Based on this result, a new preparation method of cellulose aerogels has been proposed using inorganic salt-induced gelation followed by solvent exchange and supercritical CO2 drying. According to the SEM, N2 adsorption and mercury intrusion measurements, the porous structure of cellulose aerogel made through salt-induced gelation is characterized as follows: in the mesopore range, the specific surface area is 284 m2/g, the pore volume 2.0 cm3/g and the average pore diameter 20.5 nm, in the macropore range, the pore volume is 13.95 cm3/g, the average pore diameter 0.732 μm and the porosity 91%.

Key words: cellulose, gelation, organic salt, induction, aerogel

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