多元醇PE-AMP二元体系相图

Phase diagram of binary system PE-AMP

多元醇在固-固相变时能够可逆地吸收和释放大量的热而被用于贮热材料。为了选择适宜的贮热材料,对季戊四醇(PE)和2-氨基-2-甲基-1,3-丙二醇(AMP)两种多元醇利用差热分析(DTA)、X射线衍射和变温红外光谱3种技术构筑了二元体系相图。由所得PE-AMP二元相图可知,在一定的组成范围内相图中存在3个相平衡温度:低转析温度86℃、低共析温度143℃和转熔温度176℃。X射线衍射确定了二元体系不同温度下的相态。变温红外光谱测得多元醇—OH特征吸收峰位移发生突跃的温度区间恰好与体系各自DSC测得的相转变温度相吻合,多元醇的晶体结构、分子的大小是影响二元体系不同相态间互溶度的重要因素。

Polyalcohols exhibit crystalline transformation which reversibly absorb and release a large amount of heat and can be used for thermal energy storage. The experimental phase diagram of binary system, pentaerythritol-2-amino-2-methyl-1,3-propanediol （PE-AMP）, was established by three kinds of techniques, differential thermal analysis （DTA） method, X-ray diffraction and IR spectra at various temperatures. The phase diagram was characterized by three invariant equilibria, a peritectoid at 86℃, and, a eutectoid at 143℃, and a peritectic at 176℃. X-ray diffraction was used to determine the phase structure of the binary system at different temperature. The temperature of solid-solid phase transition for polyalcohols measured by the DTA method was consistent with the results of IR, in which the -OH stretching absorptions in infrared spectra of two polyalcohols and their binary system shifted to a higher wavenumber. The miscibility of the system was discussed on the basis of intermolecular interactions between ordered low-temperature phase and orientationally disordered high-temperature phase.