用动态吸附装置分别测定了不同小分子渗透物在两种不同结构的聚酰亚胺(PI)膜中的吸附行为,计算了反常扩散指数(dw);通过分析反常扩散指数比较了不同小分子在聚酰亚胺膜中的吸附特性.研究结果表明:不同溶剂水、甲醇、乙醇、异丙醇分子在PI膜中的扩散速度顺序为:水〉甲醇〉乙醇〉异丙醇,PI膜的反常扩散指数随以上顺序逐渐增大.
The adsorption behaviors of different small molecular permeates in two kinds of polyimide pervaporation membranes with different chemical structures were studied by a set of dynamic adsorption equipment, and their adsorption properties were compared by using the calculated anomalous diffusion index (dw). The results show that the diffusion rates of different permeates in PI membranes are in the order of water 〉 methanol 〉 ethanol 〉 isopropyl alcohol, while the value of dw is in the opposite order.