文献类型：期刊文献

英文题名：Nanofibrillar cellulose aerogels

作者：Jin, Hao[1]; Nishiyama, Yoshiharu[2]; Wada, Masahisa[2]; Kuga, Shigenori[2]

机构：[1]E China Univ Sci & Technol, Chem Engn Coll, Shanghai 200237, Peoples R China;[2]Univ Tokyo, Grad Sch Agr & Life Sci, Dept Biomat Sci, Bunkyo Ku, Tokyo 1138657, Japan

年份：2004

卷号：240

期号：1-3

起止页码：63

外文期刊名：COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS

收录：;EI(收录号：2004268233514);WOS:【SCI-EXPANDED(收录号:WOS:000222519100007)】；

语种：英文

外文关键词：cellulose hydrogel/aerogel; freeze drying; solvent-exchange drying; surface area

摘要：Highly porous aerogels consisting of cellulose nanofibrils were prepared by dissolution/regeneration of cellulose in aq. calcium thiocyanate followed by regeneration and carefully controlled drying. The influence of drying method (regular freeze drying, rapid freeze drying, and solvent exchange drying) on resulting porosity was studied by electron microscopy and nitrogen adsorption. While regular freeze drying caused significant coalescence of microfibrillar units, solvent exchange drying gave highly porous aerogel composed of approx. 50 nm-wide cellulose microfibrils. Correspondingly, specific surface area of the solvent-exchange-dried aerogels ranged 160-190 m(2)/g, in contrast to 70-120 m(2)/g of regular freeze-dried materials. Rapid freeze technique using liquid nitrogen-cooled metal plate gave aerogel sheets with asymmetrical porosity, with the face contacted by copper having porous structure similar to those of solvent-exchange dried material. (C) 2004 Elsevier B.V. All rights reserved.