中国科技论文在线

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2005年03月03日

【期刊论文】甲壳素类液晶高分子的研究Ⅷ1N-邻苯二甲酰化壳聚糖PDMSO液晶溶液的热致相转变*

董炎明，吴玉松，阮永红，赵雅青，王惠武，周花

高分子学报，2003，（5）714～717，-0001，（）：

-1年11月30日

合成了氮上完全取代的邻苯二甲酰化壳聚糖（PhthCS）。用DSC研究了PhthCSPDMSO液晶溶液的热致相转变。偏光显微镜和DSC测定都表明临界浓度为43wt%。在浓度高于43wt%的溶液的DSC曲线中观察到了除了液晶-各向同性液体转变（清亮点）外还有一个明显的凝胶-溶胶转变，凝胶-溶胶转变温度和转变焓均比文献报道的不规则取代的N-邻苯二甲酰化-O-乙酰化壳聚糖大得多，可见取代的规整性对凝胶-溶较转变有很大的影响。根据DSC研究结果绘制了PhthCSPDMSO体系的相图。

SC,，壳聚糖,， N-邻苯二甲酰化壳聚糖,，溶致液晶,，热致相转变,，清亮点,，凝胶-溶胶转变

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2005年03月03日

【期刊论文】Influence of degree of N-butyrylation on critical concentration of N-butyrylated chitosan/dichloroacetic acid liquid crystalline solution

董炎明， Yanming Dong， Congyi Xu， Jianwei Wang， Yusong Wu， Yonghong Ruan， Mian Wang

Polymer Bulletin 45, 495-500 (2001)，-0001，（）：

-1年11月30日

摘要

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2005年03月03日

【期刊论文】Studies on Glass Transition Temperature of Chitosan with Four Techniques

董炎明， Yanming Dong， Yonghong Ruan， Huiwu Wang， Yaging Zhao， Danxia Bi

Journal of Applied Polymer Science, Vol. 93, 1553-1558 (2004)，-0001，（）：

-1年11月30日

摘要

Published online in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: Studies on the glass transition temperature (Tg) of chitosan are difficult to pursue because of the difficulty in sample preparation and the hydroscopicity of samples. There are a few works concerning this principal relaxation of chitosan. Among them, several quite different values (150℃, 161℃, and 203℃) have been reported. In this paper, the Tg of chitosan (140～150℃) was determined by means of four techniques, namely, dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), thermally simulated current spectroscopy (TSC), and dilatometry (DIL). DSC measurement has been assumed not to be sensitive enough to detect the relaxation temperature of polysaccharides. We propose a new method to improve the sensitivity of the DSC measurement. After a physical aging treatment of samples, the transition in DSC traces became much more distinct because of the enthalpy relaxation. This technique was also used to distinguish the Tg from other relaxations. The Tg of chitosan with different degree of deacetylation (D.D.) was examined by DSC. No influence of D.D. on Tg was found.

chitosan， glass transition， ageing， DSC

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2005年03月03日

【期刊论文】Influence of degree of molar etherification on critical liquid crystal behavior of hydroxypropyl chitosan

董炎明， Yanming Dong*， Yusong Wu， Jianwei Wang， Mian Wang

European Polymer Journal 37(2001)1713-1720，-0001，（）：

-1年11月30日

摘要

Hydroxypropyl chitosan (HPCS) with different degree of molar etherification (DME, from 0.6 to 6.0) were synthesized and characterized by FTIR, 1H-NMR and elemental analysis. The effect of DME on critical concentration forming lyotropic liquid crystal (C*) was investigated in three solvents (formic acid, dichloroacetic acid and water). C* increased as DME raised but presented a platform at low DME (less than about 2.6), which was explained based on both the amount and the size of flexible substituents. HPCS with DME ≥3.2 were water soluble. C* of HPCS aqueous solutions were evidently lower than those of formic acid or dichloroacetic acid solutions. Typical cholesteric texture appeared in HPCS solutions of all three solvents at proper concentrations.

Chitosan， Hydroxypropyl chitosan， Lyotropic liquid crystal， Degree of molar etherification， Critical concentration， Cholesteric texture