高等学校化学学报 ›› 2001, Vol. 22 ›› Issue (12): 2123.

• 研究简报 • 上一篇    下一篇

红外光谱法热分析液晶相变过程

吴强, 李晨曦, 李学臣, 李燕鸿   

  1. 吸附分离功能高分子材料国家重点实验室南开大学高分子化学研究所, 天津 300071
  • 收稿日期:2000-12-04 出版日期:2001-12-24 发布日期:2001-12-24
  • 通讯作者: 吴 强(1962年出生),男,副研究员,主要从事功能高分子材料和红外光谱研究.E-mail:sorp@nankai.edu.cn E-mail:sorp@nankai.edu.cn
  • 基金资助:

    国家教育部科学技术研究重点项目;国家教育部骨干教师资助计划项目资助

Thermal Analysis of Liquid Crystal Phase Transition Using FTIR Spectroscopy

WU Qiang, LI ChenXi, LI XueChen, LI YanHong   

  1. The State Key Laboratory of Functional Polymer Materials for Adsorption & Separation, Institute of Polymer Chemistry, Nankai University, Tianjin 300071, China
  • Received:2000-12-04 Online:2001-12-24 Published:2001-12-24

关键词: 红外光谱, 热分析, 液晶, 相转变

Abstract: Thermal spectra of liquid crystal, pndodecyloxy benzoic acid were collected at 26-150 ℃ by FTIRmicrospectroscopy. Conformational apparent enthalpy differences ΔH in phase transitions have been determined by van't Hoff equation at constant pressure and plotted with temperature. Compared to DSC, these enthalpies plot with temperature could be divided into three types. The first one was long alkyl chain group which has only one apparent endothermic enthalpy peak at 95 ℃. The second one was partial carbonyl and aromatic ether groups has three endothermic enthalpy peaks in the phase transition. The third type including benzoyl group which has one exothermic enthalpy peak at 95 ℃ and a broad endothermic enthalpy peak in the range of 128-140 ℃. These differences indicated that oxybenzoic acid part of dodecyloxy benzoic acid recrystallized to cycle dimer during alkyl chain melting in crystalsmectic phase transition.

Key words: FTIR spectroscopy, Thermal analysis, Liquid crystal, Phase transition

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