Creation of Ultrafiltration Hollow Fiber Membranes Based on Polyphenylene Sulfone with Different Chemical Structure of End Groups

To obtain high-performance ultrafiltration hollow fiber membranes, polyphenylene sulfones (PPSF) with different chemical structure of end groups were synthesized. The synthesis of PPSF was carried out in dimethylacetamide at different ratios of 4,4′-dihydroxydiphenyl and 4,4-dichlorodiphenylsulfone monomers. Samples with a predominant content of hydroxyl and chlorine end groups were studied using NMR and GPC methods. For the synthesized polymers, the hydrophilicity of the materials was studied, and phase diagrams were constructed where N-methyl-2-pyrrolidone (NMP) was used as a solvent and polyethylene glycol with an average molecular weight of 400 g/mol (PEG-400) as a porogen. Using the dry-wet spinning method, hollow fiber membranes with an average pore diameter of 11–13 nm and finger-shaped macrovoids in the substrate layer were obtained from PPSF/NMP/PEG-400 (20/60/20 wt.%) spinning solutions. An increase in the share of –OH end groups increases the hydrophilicity of the polymer. This, in turn, made it possible to obtain hollow fiber membranes based on PPSF–OH with water permeability of 42 L/(m2·h), which is 1.8 times greater than the permeability of the PPSF–Cl membrane. Both membranes demonstrate a retention coefficient of 94.7–97.3% according to Blue Dextran calibrant (M_w = 70,000 g∙mole^–1).