Preparation of parallel-oriented cellulose and molecular orientation of natural cellulose

1.改进了模型纤维低聚糖的合成方法：在已有的纤维卡他糖合成方法的基础上，建立了收敛法高产率合成纤维卡他糖的方法。该方法可应用于高聚合度化合物的制备，也可应用于纤维素的化学合成.烷基化纤维低聚糖的合成和性质：13EA04：合成了这些化合物，仅在分子的还原端具有长烷基链。这些化合物均表现出近晶织构的热致液晶性质。这些结果有力地表明，烃链通过货车范德华相互作用结合在一起，使分子以平行取向排列.平行取向纤维素的制备及天然纤维素的分子取向：建立了在纤维素分子还原端引入烷基链的方法。这些烷基纤维素的晶体结构被发现是由纤维素-II和可能-IV组成的混合物。从模型实验的结果中得到的纤维素-IV的分子取向可能是平行的。然而，需要进一步的研究来确定纤维素-IV和天然纤维素的分子取向。即使在纤维素的情况下，也表明引入的烃链使得可以控制它们的分子取向。这些发现不仅对确定纤维素-I和-II的晶体结构，而且对通过控制分子取向设计功能性聚合物具有重要意义。

1. Improved method for the synthesis of model cellooligosaccharides :High yield synthesis by convergent method was established based on the data of the synthesis of celloocataose developed so far. This method may applied to the preparation of the higher DP compounds, and also to the chemical synthesis of cellulose.2. Synthesis and properties of alkylated cellooligosaccharides : 13EA04 : These compounds, with a long alkyl chain only at the reducing end in the molecules, were synthesized. All these compounds showed thermotropic liquid crystalline properties with smectic texture. These results strongly indicate that the hydrocarbon chains are held together by van der Waals interactions to align the molecule in the parallel orientation.3. Preparation of parallel-oriented cellulose and molecular orientation of natural cellulose :The method introducing an aklyl chain at the reducing end of cellulose molecule was established. The crystal structures of these aklyl celluloses were found to be a mixture consisting of Cellulose-II and probably-IV.The molecular orientation of the Cellulose-IV obtained may be parallel from the results of model experiments. Further investigation, however, is needed for the determination of the molecular orientation of the Cellulose-IV and natural cellulose. Even in case of cellulose, it is indicated that the hydrocarbon chains introduced make it possible to control their molecular orientation. These findings may be important not only for determining crystal structures of Cellulose-I and-II, but also for desinging fuctional polymer by the controlled molecular orientation.