HAN-H_2O 二元体系玻璃化转变温度的依数性及其突变

用ＤＳＣ研究了ＨＡＮ－Ｈ２Ｏ二元体系的玻璃化转变温度Ｔｇ与Ｈ２Ｏ含量的关系，发现在一定的Ｈ２Ｏ含量范围内，玻璃化转变温度具有依数性。根据Ｔｇ的变化规律初步推测该二元体系的分子结构，认为ＨＡＮ－Ｈ２Ｏ二元体系可随Ｈ２Ｏ含量的不同而形成ＨＡＮ／Ｈ２Ｏ摩尔比不同的分子簇，而一个ＨＡＮ分子最多能与三个Ｈ２Ｏ分子形成分子簇，当Ｈ２Ｏ含量８超过７５ｍｏｌ％（ＨＡＮ／Ｈ２Ｏ摩尔比为１／３）时，只能形成ＨＡＮ／Ｈ２Ｏ摩尔比为２／３的稳定分子簇。

The Colligative Property of Glass Transition Temperature and its Sudden Change for HAN H 2O System

The dependence of the glass transition temperature (T g) of binary system of hydroxylammonium nitrate water (HAN H 2O) on the content of H 2O has been investigated by DSC. It was found that T g of the binary system exhibits the colligative property in the concentration range of 25 82 mol% HAN and when HAN concentration is decreased as low as 25 mol%, the property disappears and the T g rises surprisingly and is concentration independent. An attempt have been made to interpret this behaviour in terms of the molecular clusters formed by various mole ratios of HAN/H 2O which change with the content of H 2O in the system. It is considered that at most three moleculae of H 2O can be incorporated with one HAN to form into the cluster, but when the content of H 2O inceases as high as 75 mol % (the mole ratio of HAN/H 2O is 1/3), only cluster of 2/3 mole ratio of HAN/H 2O is formed and is the most stable.