甲壳素类液晶高分子的研究Ⅲ.取代度和分子量对氰乙基壳聚糖液晶性的影响  

STUDIES ON CHITIN\|BASED LIQUID CRYSTALLINE POLYMERS Ⅲ. EFFECT OF DEGREE OF SUBSTITUTION AND MOLECULAR WEIGHT ON THE LIQUID CRYSTALLINE BEHAVIOR OF CYANOETHYL CHITOSAN

作　　者：袁清[1] 董炎明[1] 汪剑炜 

机构地区：[1]厦门大学材料科学系

出　　处：《高分子学报》2000年第1期5-8,共4页Acta Polymerica Sinica

基　　金：中国科学院纤维素开放研究实验室资助;国家自然科学基金;福建省自然科学基金

摘　　要：研究了氰乙基取代度和分子量两种结构因素对氰乙基壳聚糖（ＣＮＣＳ） 溶致液晶性的影响，结果表明取代度的变化（ 从０－３６ 变化到１－２１） 对ＣＮＣＳ在二氯乙酸（ＤＣＡ） 中的临界浓度基本没有影响，而随着分子量的提高，ＣＮＣＳ溶致液晶的临界浓度显著降低．临界浓度存在大的分子量依赖性表明ＣＮＣＳ有较大的链刚性．Alkali\|chitosan method was employed to synthesize cyanoethyl chitosan (CNCS) with different degree of substitution (DS) from chitosan by controlling the reaction time.The effect of DS (from 0.36 to 1.21) on the liquid crystalline behaviors of CNCS was investigated.The change of DS showed no obvious influence on the critical concentration (\%C\%\+*) of liquid crystalline\|isotropic transition for CNCS/dichloroacetic acid (DCA) solution,because a small substitution degree is large enough to destroy most of the inter\|and\|intramolecular hydrogen banding.High molecular weight ( M W) chitosan was depolymerized by nitrous acid to get chitosans of different M W,proceeded by cyanoethylation using alkali chitosan method to synthesize CNCS of different M W.Investigation was carried to the determine the effect of M W on the lyotropic liquid crystalline behaviors of CNCS.The C \+* of CNCS/DCA solution decreased significantly with the increase of M W.The relatively low C \+* of CNCS and their obvious dependence on M W imply that CNCS is a semi\|rigid natural polymer with relatively high chain rigidity.

关 键 词：壳聚糖 氰乙基壳聚糖 溶致液晶 取代度 液晶性 

分 类 号：O753.2[理学—晶体学]