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

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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.