物理化学学报 >> 2001, Vol. 17 >> Issue (11): 1049-1052.doi: 10.3866/PKU.WHXB20011118

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N-烷基壳聚糖的合成及其溶致液晶行为

吴玉松;李珺;黄剑莹;陈羚;董炎明   

  1. 厦门大学材料科学与工程系 固体表面物理化学国家重点实验室,厦门 361005
  • 收稿日期:2001-03-28 修回日期:2001-07-17 发布日期:2001-11-15
  • 通讯作者: 董炎明 E-mail:ymdong@jingxian.xmu.edu.cn

Synthesis and Characterization of Lyotropic Liquid Crystalline of N-alkyl Chitosans

Wu Yu-Song;Li Jun;Huang Jian-Ying;Chen Ling;Dong Yan-Ming   

  1. Department of Materials Science & State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005
  • Received:2001-03-28 Revised:2001-07-17 Published:2001-11-15
  • Contact: Dong Yan-Ming E-mail:ymdong@jingxian.xmu.edu.cn

摘要: 合成了一系列具有不同取代基(甲基、乙基、丙基、丁基)的壳聚糖衍生物——N烷基壳聚糖,通过控制反应物摩尔比获得了一系列不同取代度的产物.不同取代基及不同取代度的衍生物均具有溶致液晶性,考察了同一碳链不同取代度和相近取代度不同碳链长度的衍生物对其液晶临界行为的影响.结果表明:同一碳链长度时,取代度对临界浓度的影响不大;而当取代度相近时,随着碳链长度增加,临界浓度也随之增大.此结果与Onsager和Flory的刚性棒理论相符.粉末X射线衍射实验进一步证实了这一结果.

关键词: 壳聚糖, N-烷基壳聚糖, 溶致液晶, 临界浓度, X射线电子能谱, 粉末X射线衍射

Abstract: A series of new derivatives of chitosan——Nalkyl(methyl, ethyl, propyl and butyl) chitosans were synthesized. The degree of substitutions of one of the derivatives Nethyl chitosan were obtained by controlled the molar ratio of the reactants. All of the products show lyotropic liquid crystalline properties regardless of the length of the carbon chains and the degree of substitution. Critical concentration (c) of the samples were measured by polar optical microscopy(POM). The results showed that the value c didn′t varied evidently with the increase of degree of substitution(DS from 0.16~0.82) in the case of a fixed carbon chain, but rise constantly as the length of substituent group varied from methyl to butyl. The result was explained as follow:the introduction of alkyl chain not only broke down some of intermolecular and intramolecular hydrogen bond, but also changed the molecular diameter (d) of chitosan. The former makes the rigidity of molecules weakened, so c of all the derivatives were bigger than chitosan itself. As to the later, d didn′t change with the increase of DS, thus,c didn′t vary with the increase of DS; while,d became bigger as the substituent group varied from methyl to butyl, so c rise accordingly. This rule is in accordance with Onsager and Flory′s theory of the rigid club and was further confirmed by Xray diffraction experiments.

Key words: Chitosan, N-alkyl chitosan, Lyotropic liquid crystal, Critical concentration, XPS, XRD