Cloud Point and Liquid-Liquid Equilibrium Behavior of Thermosensitive Polymer L61 and Salt Aqueous Two-Phase System
Cloud Point and Liquid-Liquid Equilibrium Behavior of Thermosensitive Polymer L61 and Salt Aqueous Two-Phase System
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热敏聚合物L61与盐水两相体系的浊点和液液平衡行为
DOI：
10.1021/acs.jpcb.5b03201
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发表时间：
2015
影响因子：
3.3
通讯作者：
Ni Liang
中科院分区：
文献类型：
--
作者：
Rao Wenwei;Wang Yun;Han Juan;Wang Lei;Chen Tong;Liu Yan;Ni Liang
测定了热敏性三嵌段聚合物L 61（聚环氧乙烷-聚环氧丙烷-聚环氧乙烷）（PEO-PPO-PEO）在不同电解质（K_2HPO_4、（NH_4）_3C_6H_5O_7和K_3C_6H_5O_7）存在下的浊点。加入电解质可降低L 61的浊点，且随电解质浓度的增加，L 61的浊点呈线性下降。电解质降低浊点的效果顺序为：K_3C_6H_5O_7>（NH_4）_3C_6H_5O_7> K_2HPO_4。随着盐浓度的增加，双水相体系表现出相反转。此外，增加温度降低了可以促进相转化所需的盐的浓度。测定了L_（61）-K_2 HPO_4/（NH_4）_3C_6 H_5 O_7/K_3C_6 H_5 O_7两相体系在T =（25、30和35）°C时的相图和液液平衡数据。用四参数非线性经验公式拟合了双水相体系的相图。此外，随着温度的升高，相图中的联络线斜率和两相区面积有增大的趋势。不同盐诱导双水相体系形成的能力与盐降低浊点的能力具有相同的数量级。
The cloud point of thermosensitive triblock polymer L61, poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO), was determined in the presence of various electrolytes (K2HPO4, (NH4)3C6H5O7, and K3C6H5O7). The cloud point of L61 was lowered by the addition of electrolytes, and the cloud point of L61 decreased linearly with increasing electrolyte concentration. The efficacy of electrolytes on reducing cloud point followed the order: K3C6H5O7> (NH4)3C6H5O7> K2HPO4. With the increase in salt concentration, aqueous two-phase systems exhibited a phase inversion. In addition, increasing the temperature reduced the concentration of salt needed that could promote phase inversion. The phase diagrams and liquid–liquid equilibrium data of the L61-K2HPO4/(NH4)3C6H5O7/K3C6H5O7aqueous two-phase systems (before the phase inversion but also after phase inversion) were determined atT= (25, 30, and 35) °C. Phase diagrams of aqueous two-phase systems were fitted to a four-parameter empirical nonlinear expression. Moreover, the slopes of the tie-lines and the area of two-phase region in the diagram have a tendency to rise with increasing temperature. The capacity of different salts to induce aqueous two-phase system formation was the same order as the ability of salts to reduce the cloud point.