多元醇二元体系固-固相变机理的研究*

摘要

Many polyalcohols can change from one crystal structure to another in solid state at certain temperatures. A lot of papers reported their phase transition enthalpy, transition temperatures, and phase diagrams. This paper investigates the relation between transition enthalpy and hydrogen bond for the NPG (Neopentylglycol) and PE (Pentaerythritol) binary system on the basis of infrared spectrum experimental data and calorimetric results. It is shown that in the binary system some of the associated hydrogen bonds become weaker and are easier to break up. When temperature rises to a certain value, the hydrogen bonds, which retain in the course of phase transformation from the phase of NPG in PE to the plastic phase, will break up and form the second endothermal peak on the calorimetric curve. The number of retained hydrogen bonds is larger for the binary system NPG/PE with higher NPG concentration, and as a result, the corresponding enthalpy for the second endothermal peak is larger. While the influence of NPG on the retained hydrogen bonds is larger for binary system NPG/PE with higher NPG concentration, and the corresponding temperature of the second endothermal peak is lower.%多元醇在一定温度下发生固-固相变，大量文献都报道了它们的固-固相变焓、相变温度以及相图。本文以红外光谱测试结果以及量热实验结果为基础，探讨了新戊二醇/季戊四醇二元体系的固-固相变焓与氢键的关系：二元体系中部分分子间氢键变弱，变弱的氢键更易于断裂；温度上升到一定值，新戊二醇在季戊四醇中的相向塑性晶体相相变时保留下来的氢键断裂，形成二元体系的量热曲线的第二个吸收峰；高新戊二醇浓度的二元体系，可能保留下来的氢键数量少，第二个吸收峰对应的焓值小，但保留的氢键受新戊二醇影响更大，第二个吸收峰对应的温度更低。