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采用碱壳聚糖的方法合成了一系列具有不同摩尔醚化度 (DME)的新的液晶性壳聚糖衍生物羟乙基壳聚糖 (HECS) .用酸氧化蚀刻的方法 ,在扫描电子显微镜 (SEM )下证实了其胆甾型的液晶织构 .以甲酸为溶剂 ,研究了摩尔醚化度对羟乙基壳聚糖溶致液晶性的影响 .结果表明 ,在该体系中 ,摩尔醚化度能综合取代基个数及长度两个结构因素的影响 ,当DME较低时 (<～ 2 0 ) ,这种影响关系类似于取代基个数 (即取代度 )的影响 ,当DME较高时 (>～ 2 0 ) ,则类似于取代基长度的影响 .前者对液晶临界浓度的影响很小 ,而后者却有显著影响 .此外还观察到当DME >～ 2 0时出现水溶性 ,HECS的水溶液也呈现典型的胆甾指纹状织构
A series of hydroxyethyl chitosan (HECS), a new liquid crystalline chitosan derivative with different molar etherification degree (DME), was synthesized by the method of alkali chitosan.Using acidic oxidation etching method, The cholesteric liquid crystal texture was confirmed by scanning electron microscopy (SEM). Formic acid was used as a solvent to study the effect of the degree of etherification on the lyotropic liquid crystallinity of hydroxyethyl chitosan. The results showed that molar ratio The degree of etherification can be affected by the combination of the number of substituents and the length of the structure. When the DME is low (<~ 20), the influence is similar to the effect of the number of substituents (ie degree of substitution) Higher (> ~ 20), similar to the length of the substituent effect of the former has a small impact on the critical concentration of the liquid crystal, while the latter have a significant impact on the other also observed when DME> ~ 20 water-soluble , HECS aqueous solution also presents a typical cholesteric fingerprint texture