Open AccessMechanism of polyalcohol solid—solid phase change
Author(s) -
Xiaowu Wang,
Xu Hai-Hong
Publication year - 2011
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.60.030507
Subject(s) - enthalpy , phase change , hydrogen bond , thermodynamics , phase (matter) , phase diagram , materials science , pentaerythritol , chemistry , organic chemistry , physics , molecule , fire retardant , composite material
Many polyalcohols will change from one crystal structure to another at certain temperatures. A lot of works had reported their phase change enthalpy, phase change temperature and phase diagram. It is taken that their phase change enthalpy must be related to their hydrogen bond. This article investigated quantitatively the relation between phase change enthalpy and hydrogen bond of NPG (neopentylglycol), PG (pentaglycerino) and PE (pentaerythritol) on the basis of infrared spectrum experimental data and calorimetric results. It was shown that before phase change, all the —OH are associated and as a result NPG, PG and PE form layer structure. After phase change, NPG, PG and PE move along the layer and as a result some hadrogen bonds break. Therefore the phase change enthalpy equals the energy used to break hydrogen plus the energy used to increase the vibration frequency of other still associated —OH.