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

研究主要从两个方面展开。一种是通过重新定向高结晶纤维素微晶来生产先进的纤维素材料。另一种是采用两相晶体模型来解释x射线衍射数据的差异。关于纤维素微原纤维的重定向，我们研究了微晶体在高达20特斯拉（20000高斯）的强静磁场下在水悬浮液中的行为。磁场越强，定向效果越好。纤维素微晶的分子轴取向与电场方向垂直。这种行为也通过计算晶体的抗磁化率得到证实。考虑到两相晶体模型的适用性，我们首先研究了12种高结晶的天然纤维素，并通过x射线粉末衍射法测量了纤维素的典型d间隔（四个最强烈的反射，对应的d间隔约为0.6,0.53,0.39,0.26 nm）。通过对观察到的d间距数据进行判别分析，可以将天然纤维素分为两类；一种是富含i - β成分的agal -细菌型纤维素，另一种是以i - β为主的棉-苎麻型纤维素。分析结果表明，陆生植物原生纤维素（包括木质纤维素）均为棉-苎麻型，纤维素以Ibeta组分为主。

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.