期刊
POWDER DIFFRACTION
卷 23, 期 2, 页码 92-95出版社
CAMBRIDGE UNIV PRESS
DOI: 10.1154/1.2912442
关键词
cellulose; hydrogen bond; neutron crystallography; X-ray crystallography; fiber
X-ray and neutron fiber diffraction has been used to study cellulose as it is converted from its naturally occurring crystal phase, cellulose I, to an activated crystal phase, cellulose IIII, by ammonia treatment. The detailed crystal structures determined for cellulose I-beta, an intermediate ammonia-cellulose I complex, and cellulose IIII, reveal a structural transition pathway: hydrogen bonded sheets of chains in cellulose I-beta slip with respect to each other to accommodate the penetrating ammonia guest molecules in the intermediate complex. On evaporation of ammonia from the intermediate complex, there is a relative small change in chain packing as an inter-sheet ammonia bridge is replaced by an inter-sheet hydrogen bond in cellulose IIII. When cellulose IIII is heated it converts back to cellulose I-beta-Both ammonia-cellulose I and cellulose IIII have extended chains of cooperative hydrogen bonds in relatively open crystal structures that may add to their susceptibility to rapid change. (c) 2008 International Centre for Diffraction Data.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据