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Structure Analyses of native celluloses on the basis of 2 phase crystal model

基于两相晶体模型的天然纤维素结构分析

基本信息

批准号：
03660163
负责人：
SUGIYAMA Junji
金额：
$ 1.28万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

The research was mainly extended into two directions. One is to produce advanced cellulosic materials by reorientating highly crystalline cellulose microcrystals. The other is to apply 2 phase crystal model in order to explain the varietal differences of X-ray diffraction data. Regarding reorientation of cellulose microfibrils, we have investigated the behavior of microcrystals in the aqueous suspension under strong static magnetic fields up to 20 Tesla (20000 Gauss). The stronger the magnetic field, the better orientation was achieved. Cellulose microcrystals was oriented with their molecular axes perpendicular to the direction of the field. This behavior was also confirmed by calculation of the diamagnetic susceptibility of the crystal. Regarding the applicability of 2 phase crystal model, we first investigated 12 highly crystalline native celluloses, and measured typical d-spacings for celluloses (four most intense reflections; corresponding d-spacings are about 0.6, 0.53, 0.39, 0.26 nm) by an X-ray powder diffractometry method. By discriminant analyses of observed d-spacing data it was possible to distinguish native celluloses into two category ; one is Agal-Bacterial type cellulose being rich in Ialpha component, and the other is Cotton-Ramie type celluloses dominated by Ibeta. According to this analyses, native celluloses from terrestrial plants (including wood celluloses) were all discriminated into Cotton-Ramie type, cellulose dominated by Ibeta component.

研究主要从两个方向展开。一种是通过重定向高度结晶的纤维素微晶来生产高级纤维素材料。二是应用两相晶体模型解释X射线衍射数据的品种差异。关于纤维素微纤丝的重新取向，我们已经研究了在高达20特斯拉（20000高斯）的强静磁场下的水悬浮液中的微晶的行为。磁场越强，获得的取向越好。纤维素微晶的取向与它们的分子轴垂直于场的方向。这种行为也证实了晶体的抗磁化率的计算。关于2相晶体模型的适用性，我们首先研究了12种高度结晶的天然纤维素，并通过X射线粉末衍射法测量了纤维素的典型d-间距（四种最强的反射;相应的d-间距约为0.6，0.53，0.39，0.26 nm）。通过对d-间距数据的判别分析，可以将天然纤维素分为两类：一类是富含I α组分的Agal-Bacterial型纤维素，另一类是以I β组分为主的Cotton-Ramie型纤维素。结果表明，陆生植物天然纤维素（包括木质纤维素）均属于棉-麻纤维素类型，纤维素组分以I β组分为主。