【摘要】 水溶性聚合物水溶液中存在聚合物和水之间的氢键缔合化学平衡 ,溶液的混合Gibbs自由能由氢键缔合化学平衡和Flory Huggins理论二部分组成 ,在此基础上建立了能描述水溶性聚合物液 -液平衡的氢键缔合模型。将该模型用于研究PEG2 180 -水和PEG2 2 90 -水两个体系的液 -液相平衡 ,计算值能较好地吻合实验值。由该模型得到的氢键生成焓的数值和符号能够用于解释在水溶性聚合物水溶液中 ,存在低临介溶液温度 (LCST)的现象。应用氢键缔合模型计算了水溶液中水的化学位。在不同温度下水的化学位随聚合物体积分率的变化规律 ,能够阐明同时存在高临介溶液温度 (UCST)和低临介溶液温度 (LCST)的水溶性聚合物液 -液相平衡的特征更多还原

【Abstract】 In aqueous water soluble polymer solutions it is assumed to exist a hydrogen bonding association equilibrium between the polymer and water. The Gibbs free energy of mixing is taken as the sum of two contributions: one is the contribution from hydrogen bonding association equilibrium and another one is from the Flory Huggins theory. Based on these considerations, a new association model is put forward. This model is applied to correlate and predict the liquid-liquid equilibria of poly (ethylene glycol) 2180 water and poly (ethylene glycol) 2290 water systems and a fairly good agreement between the calculated and experimental liquid-liquid equilibrium compositions is obtained. The magnitudes and signs of the enthalpy of formation of hydrogen bonds that are estimated from this association model can be used to explain the existence of lower critical solution temperature in liquid-liquid equilibrium of aqueous water soluble polymer solution. The model is used to calculate the chemical potential of water. The variation of the chemical potential of water with the volume fraction of polymer at several temperatures illustrate the features of liquid-liquid equilibrium of aqueous water soluble polymer solution with both lower critical solution temperature and upper critical solution temperature.更多还原