Poly(ether sulfone) (PES) hollow-fiber membranes prepared from various spinning parameters

• Fabricate PES hollow-fiber by a steam/dry/wet phase inversion method
• Analysis effects of various spinning conditions on PES properties
• The PWP increases about 300%, keeping BSA rejection above 99% with PEG concentration
• The mechanical properties were depending on the PEG, bore fluid type and flow rates.

A steam/dry/wet phase inversion method was used to fabricate hollow-fiber membranes for ultrafiltration (UF) applications from polyethersulfone (PES) as a polymer material, gamma butyrolactone (GBL) as a solvent and polyethylene glycols (PEGs) as a pore-former additive. Pure water, 30 wt.% ethanol and 30 wt.% isopropanol were used as bore fluids. The effect of PEG concentration, type of bore fluid, and bore fluid flow rate (BFR) on the structure, permeability, separation performance and mechanical properties of PES hollow fiber was studied. The PES hollow-fiber membranes were characterized by scanning electron microscopy (SEM), capillary flow porometer and porosity measurement. From the results it was found that all PES hollow fibers have a sponge-like structure in the cross-sectional area. Using 30% ethanol as a bore fluid produced fiber with pore density higher than that produced using water or 30% isopropanol. With an increase of the bore fluid rate from 7.67 to 23.06 g/min, the pore density and the PWP increased from 14,698.6 to 29,440.2 (pores/mm2 × 102) and from 45.2 to 107.4 l/m2·h·bar respectively, with a minor change in protein rejection. The mechanical properties in terms of Young's modulus, tensile strength and elongation at break were dependent on PEG concentration, and bore fluid type and concentration.