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

1. 模型纤维素低聚糖合成方法的改进：在目前纤维素低聚糖合成数据的基础上，建立了收敛法高产率合成方法。该方法可用于高DP化合物的制备，也可用于纤维素的化学合成。烷基化纤维低聚糖的合成与性质：13EA04：合成了这些仅在分子还原端具有长烷基链的化合物。这些化合物均表现出热致液晶性质，具有近晶织构。这些结果有力地表明，烃类链是通过范德华相互作用结合在一起的，使分子沿平行方向排列。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丙烯链的方法。发现这些丙基纤维素的晶体结构是由纤维素- ii和可能- iv组成的混合物。所得的纤维素- iv的分子取向与模型实验结果可能是平行的。然而，纤维素- iv和天然纤维素的分子取向还需要进一步的研究。即使在纤维素的情况下，烃类链的引入也使得控制其分子取向成为可能。这些发现不仅对确定纤维素i和纤维素ii的晶体结构，而且对通过控制分子取向设计功能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.