磺化聚醚酰亚胺/聚醚酰亚胺共混膜的结构与性能

Structures and Properties of Sulfonated Polyetherimide/Polyetherimide Blend Membranes

将亲水性的磺化聚醚酰亚胺(SPEI)和疏水性的聚醚酰亚胺(PEI)共混,以N,N 二甲基乙酰胺(DMAc)为溶剂,制备了SPEI(Na型)/SPEI中空纤维超滤膜,研究了纺丝过程中内凝固浴组成比例和空气间隙距离变化对膜结构以及膜分离性能的影响。实验结果表明,随着内凝固浴中DMAc含量的提高,纤维内指状孔减少,水通量下降,而截留率则不受影响;随着空气间隙距离的增大,从膜内壁侧出发的指状孔结构前端逐渐向外壁发展,而膜的外壁侧则逐渐变得致密,同时,膜的外表面可能出现较大的微孔结构,导致膜的水通量随着空气间隙距离的增加而迅速增加后随之下降,而截留率则一直保持下降趋势。

Sulfonated polyetherimide/polyetherimide (SPEI/PEI) ultrafiltration hollow fiber membranes were prepared with phase inversion method and SPEI in Na form was used as a polymer additive. It is found that, with the increase of N, N-dimethyl acetamide in the internal coagulant, the pure water permeation flux decreased gradually while the retention kept almost constant for the membranes. On the other hand, it seems that both the pure water permeation flux and the retention of these SPEI/PEI membranes decreased significantly with the increase of air gap distance for membrane spinning. All these results could be ascribed to the structure changes which were observed characterized by scanning electron microscopy.