Manipulation of phase inversion, membrane morphology and performance through blending polyethersulfone and bisphenol S copoly (phthalazinone ether sulfone)

The growing demand for efficient separation technologies has spurred research into advanced materials. This study fabricates polyethersulfone (PES)/bisphenol S copoly (phthalazinone ether sulfone) (PPESS) hollow fiber membranes via solution blending to overcome performance-cost trade-offs in traditional single-material membranes. The compatibility of the two components was confirmed by DSC. The effects of different component contents in the formula on the thermodynamic stability, phase separation kinetics of the casting liquid and final membrane morphology were systematically investigated. Increasing the PPESS ratio, polymer concentration, or polyvinylpyrrolidone (PVP) additive content reduced the thermodynamic stability of the system and delayed phase separation to varying extents. This consequently led to a decrease in membrane pore size and increased the bovine serum albumin (BSA) rejection rate to above 95%. Considering permeability-selectivity trade-off, under a suitable spinning process, the blended membrane prepared with a PES/PPESS ratio of 8:2, a polymer content of 18 wt%, and a PVP content of 4 wt% exhibited the best overall performance, achieving a pure water flux of 109.5 L m −2  h −1 and a BSA rejection rate of 91.9%.