界面聚合制备复合膜过程的数学模型

Mathematical Model for Fabrication of the Composite Membranes by Interfacial Polymerization

基于高分子物理化学、质量传递和相分离成膜理论,研究在复合膜制备过程中采用界面聚合反应成膜的机理,建立了非稳态条件下反应-扩散联合控制的数学模型;通过有针对性地简化,该模型可适用于反应控制和扩散控制。模型中无量纲参数有明确的物理意义,较好地反映了界面聚合反应成膜过程的机理。无量纲化处理使模型解析解形式更为简单、实用,模型与实验数据吻合良好,且优于现有模型。通过模拟计算,可得出单体(A组分)浓度、膜的厚度、膜厚增长率随时间的变化关系,并可考察聚合反应速率常数、单体(A组分)在复合层中的扩散系数、单体初始浓度等参数对成膜过程的影响,理论结果可用于指导界面聚合反应成膜实践。

A theoretical model for fabrication of the composite membranes by interfacial polymerization is established. The model can describe the process of interfacial polymerization controlled by both diffusion and reaction under non-steady-state conditions depending on the polymer chemistry, mass transfer and the polymer phase separation. The model is simplified by introducing some dimensionless parameters which have definite physical meanings, and then is solved to obtain analytical solutions. The concentration distribution of monomer A, the thickness of selective film and the growth rate of the thin film, as the function of reaction time during interfacial polymerization, can be easily obtained by model calculation based on the parameters such as reaction rate constant, the diffusion coefficient, the initial concentration of monomer, etc. The model is in good agreement with experimental data, and it is superior to the previous model. The model can provide an important guide for fabricating the composite membranes by interfacial polymerization.