Helical Structure and Supramolecular Structure of Cellulose Derivatives in Solution

在本研究项目中，我们研究了纤维素衍生物，纤维素三（苯基氨基甲酸酯）（CTC）在溶液中的局部构象，液晶性和浓溶液的动力学性质（粘度和扩散）。研究结果如下。(1)从先前的构象能量计算可知，纤维素链中的每个葡萄糖残基具有两种能量稳定的构象（左旋3/1螺旋和延伸的2/1螺旋）。从特性粘数对温度和分子量的依赖性研究了纤维素链在溶液中的局部构象。(2)确定CTC的浓缩THE溶液的反相形成的临界浓度作为分子量的函数。结果进行了有利的统计力学理论相比，刚性链聚合物的解决方案。(3)从稀释到浓缩方案的CTC溶液的零剪切粘度作为CTC的分子量和浓度的函数进行测量。（4）用动态光散射和脉冲场梯度核磁共振分别测定了CTC在THF溶液中的互扩散系数和自扩散系数，并与刚性链聚合物溶液动力学理论（模糊圆柱体理论）进行了比较。虽然后一个系数与模糊圆柱理论相比是有利的，但前一个系数则不然。(5)CTC的胆甾型THF溶液转变为无色凝胶，随着聚合物浓度的增加，无色凝胶消失。开始了这种凝胶化行为的初步实验。

In this research project, we have investigated the local conformation in solution, liquid crystallinity and dynamic properties (viscosity and diffusion) of concentrated solutions for a cellulose derivative, cellulose tris(phenyl carbamate) (CTC). The research results are as follows.(1) It is know that each glucose residue in the cellulosic chain takes two energetically stable conformations (a left-handed 3/1 helix and extended 2/1 helix) from previous conformation energy calculations. The local conformation of the cellulosic chain in solution was investigated from the temperature and molecular weight dependencies of the intrinsic viscosity.(2) The critical concentration for the cholesteric phase formation for concentrated THE solutions of CTC was determined as a function of the molecular weight. The results were favorably compared with a statistical mechanical theory for stiff-chain polymer solutions.(3) Zero-shear viscosities of THE solutions of CTC from dilute through concentrated regime were measured as functions of the molecular weight and concentration of CTC. The results were favorably compared with a theory for polymer dynamics (the fuzzy cylinder theory) for stiff-chain polymer solutions(4) The mutual-and self-diffusion coefficients for THF solutions of CTC was measured up to a concentrated regime by dynamic light scattering and pulse-field gradient NMR, respectively. While the latter coefficient was favorably compared with the fuzzy cylinder theory, the former coefficient was not.(5) Cholesteric THF solutions of CTC were trartsformed into cholesteric gels and then the cholesteric color was disappeared with increasing the polymer concentration. A preliminary experiment for this gelation behavior was started.