Structural analysis of native cellulose and its derivatives by direct imaging of molecular chains

经过4年的深入研究，得出了以下结果：1)利用电子衍射对2种天然纤维素进行了研究，这些天然纤维素经^<13>C-NMR分类为细菌-缬草型和棉-苎麻型。他们分别被分配到三斜和单斜的混合阶段和单斜的单相。2)三斜单元只含一条链。因此，同一微纤维中的所有链具有相同的聚合度。因此，提出了一种全新的模型，这是本庶渡边的8链单元电池的一个很好的替代方案。3)在软木、硬木和竹子等木质纤维素中，我们指出了它们的衍射强度和间距数据的差异。基于这些数据的判别分析表明，17种软木和61种硬木的木质样品的整体纤维素都被归类为棉-苎麻类型，尽管有15种软木和7种硬木在纯化前曾被归类为细菌-瓦洛瓦类型。然而，软木和硬木之间仍然存在某些差异。4)纤维素的丝光作用，即纤维素I转化为II，是一个不可逆的过程。研究了溶胀初期的中间结晶碱性纤维素，发现完全溶胀后的纤维素不能再回到纤维素i。5)用电镜和x射线衍射研究了分散微晶纤维素的丝光作用。晶态的改变伴随着明显的形态变化，如沿微原纤维形成裂纹和珠状颗粒的形成。(6)研究了纤维素微晶水悬浮液的抗磁取向行为。在强磁场作用下，纤维素微晶的纤维轴垂直于磁场，取向完美。

Following results were generated during 4 years of intensive research.1) 2 types of native celluloses categorized by ^<13>C-NMR, namely the Bacterial-Valonia type and the Cotton-Ramie type, were investigated by electron diffraction. They were assigned to the mixtwe of triclinic and monoclinc phases and the single phase of monoclinic, respectively. 2) The triclinic unit contained only one chain in it. Accordingly all the chains in one microfibril had the same polifity. The entirely new model were thereby proposed, which was a good alternative of 8-chain unit cell by Honjo-Watanbe. 3) Among woody celluloses such as those from softwoods, hardwoods, and bamboos, we have pointed out the difference in their diffraction intensities and dspacing data. The discriminant analyses based on those data showed that the holocelluloses of woody samples (17 softwoods and 61 hardwoods) were all categafift to the Cotton-Ramie type, although some of them (15 softwoods and 7 hardwoods) were once classified to the Bacterial-Valowa type before purification. There still remains, however, certain differences between softwoods and hardwoods. 4) Mercerization of cellulose, the transformation of cellulose I into II, is known to be an irreversible process. Having investigated intermediate crystalline alkaline celluloses in the early stage of swelling, we concluded that the fully swollen cellulose cannot go back to cellulose I. 5) Mercerization of dispersed microcrystalline cellulose was investigated by electron microscopy and x-ray diffraction. The change of crystalline state accompanied remarkable morphological changes such as the formation of cracks along microfibrils and the formation of bead-like particles. 6) The diamagnetic orientation behavior of the aqueous suspension of cellulose microcrystals was investigated When the strong magnetic field was applied, the crystals oriented perfectly, being their fiber axes perpendicular to the magnetic field.