【摘要】 利用显微红外光谱技术在宽范围的温度区域跟踪对十二烷氧基苯甲酸相变过程 ,经二维相关红外光谱分析 ,来描述对十二烷氧基苯甲酸在不同温度区间的分子动态变化。结果认为固态由烷基相互缠结以多种羧酸聚集体的状态存在 ,95℃发生的相转变主要是非均相的十二烷基熔融和氧基苯甲酸部分重结晶的过程 ,132℃以后的相转变主要是羧酸聚集体部分氢键集中断裂和羧酸苯醚基团迅速熔融的结果。更多还原

【Abstract】 Thermal spectra of liquid crystal,dodecyloxy benzoic acid were collected over a temperature range of 26-150℃ by FTIR microspectroscopy.By taking investigations of temperature induced changes in dodecyloxy benzoic acid by means of 2D infrared correlation spectroscopy,it was possible to clearly describe the molecular dynamic mechanism of dodecyloxy benzoic acid aggregates in the phase transitions.The analysis shows that p dodecyloxy benzoic acid crystallized as mutli molecule aggregates through hydrogen bonds between the carboxylic groups,while the long polymethylene residues intermixed each other in solid state.Premelting phenomena in polymethylene residues were observed with temperature up to melting point.It seems that lots of oxy benzoic acid part recrystallized to cycle dimer as supermoleculer liquid crystal during alkyl chain melting in crystal smectic phase transition.After temperature over 132℃,oxy benzoic acid part were melted to open dimer and separate molecule in liquid state.更多还原