N-hydroxypropy 1 chitosan과 N,O-hydroxypropy1 chitosan의 합성 및 액정성에 관한 연구 = Preparation of N- and N,O-hydroxypropy1 chitosans and Their Liquid Crystallinity

다국어 초록 (Multilingual Abstract)

N-hydroxypropyl chitosans(N-HPCTOs) were prepared by reaction of chitosan with propylene oxide in the solvent mixture of water and ethanol, The derivatives with different total degree of substitution(DS) and molar substitution(MS) were obtained by adjusting the molar ratio of propylene oxide to glucosamine unit, the reaction pressure, the reaction temperature, and the reaction time, N.O-hydroxypropyl chitosan(N.O-HPCTO) was prepared by reaction of alkali N-HPCTO with propylene oxide in an autoclave at 70℃. The MS value and the site of substitution were determined by the FT-IR and ^1H-NMR analysis. Both the DS and the MS values of N-HPCTOs were found to be less than 2, indicating that it is difficult to add propylene oxide to the hydroxy groups in the side chain or to the amino groups in the main chain under all the experimental conditions studied. On the other hand, the DS value of N,O-HPCTO is less than 4 but the MS is larger than 4, showing that the propylene oxide molecules became more and more difficult to reach the main chain as the side chain grew. By optical microscopic observation, N.O-HPCTO, which is soluble in water as well as common organic solvents, were found to form both thermotropic and lyotropic phases. However, all the N-HPCTOs, which are soluble in the specific solvents such as water, a alcohols and formic acid, do not form thermotropic liquid crystal phases but form lyotropic phases.