Kinetic Research for Separation Function of Lonic Polymer Gel

从实验和理论上研究了凝胶溶胀行为和离子行为对外界条件（盐浓度、pH值、电场）的依赖性。研究结果如下：1.研究了电解质和pH值对含丙烯酸和三甲基-N-丙烯酰基-3-氨丙基氯化铵的丙烯酰胺凝胶溶胀行为的影响。结果表明，凝胶的溶胀行为可以用带电基团的解离和凝胶与外溶液的离子交换来解释。基于Donnan平衡理论建立的模型能够描述离子交换后凝胶的溶胀行为和凝胶中自由移动的离子浓度.根据凝胶周围的pH值分布、凝胶内Na^+浓度和脱水速率，研究了离子型水凝胶在电池中的收缩和脱水机理。研究发现，离子凝胶的收缩和脱水是通过以下过程发生的：（1）电解产生H^+和OH^-离子;（2）阳极产生的H^+离子与凝胶内最初解离的Na^+离子之间的离子交换;（3）电泳使Na^+离子在阴极附近聚集;（4）过程（3）导致阴极附近离子强度增加。因此，离子凝胶的收缩和脱水依赖于电解和Na^+离子电泳产生的H^+离子。

The dependence of gel swelling behavior and ionic behavior on external conditions (salt concentrations, pH, electric field) were investigated experimentally and theoretically. The results are as follows :1. The effects of electrolytes and pH on the swelling behavior of acrylamide gel containing both acrylic acid and trimethyl-N-acryloyl-3-aminopropyl ammonium chloride were investigated. It was found that swelling behavior could be explained to consider the dissociation of charged groups and ion exchange between the gel and the outer solution. The model based on Donnan equilibrium theory was found to describe the swelling behavior of the gel and the concentrations of freely mobile ions in the gel after ion exchange.2. The mechanism of shrinkage and dehydration of ionic hydrogels packed in an electric cell were investigated on the basis of the distribution of pH around the gel, the Na^+ ion concentration within the gels packed in the cell and the dehydration rate. It was found that shrinkage and dehydration of the ionic gels take place through the following processes :(1) generation of H^+ and OH^- ions by electrolysis ; (2) ion exchange between H^+ ions generated on the anode and Na^+ ions dissociated originally within the gels ; (3) accumulation of Na^+ ions near the cathode by electrophoresis ; and (4) increase in ionic strength near the cathode caused by process (3). Therefore, the shrinkage and dehydration of ionic gels depend on the generation of H^+ ions by electrolysis and electrophoresis of Na^+ ions.