超支化聚酯--乙二醇--水体系相行为和相关性质

Phase Behavior and Related Properties of Hyperbranched Polyester-ethylene Glycol-water Systems

分别在298.2 K、303.2 K、308.2 K、313.2 K和318.2 K温度下实验测定了超支化聚酯Boltorn H20-乙二醇-水、Boltorn H30-乙二醇-水和Boltorn H40-乙二醇-水体系的相行为以及Boltorn H20-乙二醇-水体系的密度、粘度和电导率数据。根据以上数据初步探讨了体系内分子间相互作用。研究结果表明,超支化聚酯Boltorn H聚合物(H20、H30和H40)-乙二醇-水三元体系中均存在着“最低临界共溶温度”。这三种超支化聚酯在当前体系中的相行为类似。Boltorn H20-乙二醇-水三元体系中,随着温度升高,体系中分子热运动的增强也导致密度和粘度降低而电导率增大。随着抗溶剂水的添加,氢键减弱导致密度降低,而氢键减弱和水分子在该体系中的“稀释”作用导致粘度降低。体系电导率随着Boltorn H20浓度的增大表明Boltorn H20是该体系中的主要电荷载体。

The phase behaviors for ternary systems of Boltorn H20-ethyl glycol-water, Boltorn H30-ethyl glycol-water, and Boltorn H40-ethyl glycol-water were experimentally determined at the temperatures of 298.2 K, 303.3 K, 308.2 K, 313.2 K,and 318.2 K as well as the densities, viscosities, and electrical conductivities for the system of Boltorn H20-ethyl glycol-water. These data were used to investigate the intermolecular interactions in these systems. The results showed that the lower critical solution temperatures and similar phase behaviors were found for all the three ternary systems. In the system of Boltorn H20-ethyl glycol-water, the enhancement of molecular thermal motion and weakening of hydrogen bonding led to the decreases in density and viscosity and increase in electrical conductivity with temperature. Upon the addition of antisolvent water, possible weakening of hydrogen bonding resulted in decreases in density and viscosity. Another reason for the decrease in viscosity could be the dilution effect of the water molecules. The increase in electrical conductivity with the concentration of Boltorn H20 suggested that it was the main electron carrier in the system.