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.