Preparation and characterization of hyperthin-skinned and high performances asymmetric polyethersulfone membrane for gas separation

摘要

Defect-free high performance membranes for O2/N2 separation were prepared by coating the porous polyethersulphone (PES) membrane of hyperthin-skin layer with silicone rubber. The combined effects of fabrication parameters in dry/wet phase inversion process and of the casting dope rheology enabled improved of membrane performance in O2 and N2 separation, i.e. the optimum range was found to be from 149 to 447 s~(-1) and 10 to 14 s, respectively, for the shear rate and the evaporation time to prepare the hyperthin-skinned asymmetric polyethersulfone membranes. The optimum polymer concentration was 32 wt% , 61 wt% and 7 wt% for PES, l-methyl-2-pyrrolidone and water respectively. The thinnest skin layer thickness was 538 ±95.6 A. Evaporation time and casting shear have been identified as the dominant fabrication parameters in controlling skin layer thickness and skin integrity.