Development and characterization of polysulfone/polyvinylidene flouride blend membrane induced by delayed liquid-liquid demixing

Abstract

Polysulfone (PSf)-Polyvinylidene fluoride (PVDF) membranes were fabricated via phase inversion method and immersion precipitation technique. In particular, the effect of varied amount of NMP addition into coagulation bath on permeability, mechanical properties, chemical resistance and thermal stability of membranes were investigated. The presence of solvent in coagulation bath caused delayed liquid-liquid demixing that caused increasing chance of disoriented interactions in PSf/PVDF blend membrane thus larger pore and dominated macrovoids membranes resulted. It was found that the increase of solvent addition lead to increasing of flux and decreasing of mechanical strength whereas a remarkably and enhanced chemical resistance has been achieved which showed excellent resistance in H2SO4 but degraded upon exposure to a concentration of 40% NaOH solution. Furthermore, TGA analysis revealed that the membrane exhibit improved thermal stability while the morphology of membrane showed the formation of asymmetry structure.