Structures and Properties of Sulfonated Polyetherimide/Polyetherimide Blend Membranes

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.