Study of the Influence of the Nature of the Solvent on the Performance of Polyethersulfone Membranes

The influence of solvents dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO) on the morphology and specific productivity of membranes made on the basis of polyethersulfone (PES 5900) was studied. Polyvinylpyrrolidone (PVP) is used as a pore-forming agent, which increases the hydrophilicity of the membrane and plays an important role in regulating various properties of the resulting polymer membrane.  It is shown that membranes with different surface structure and specific productivity depending on the physicochemical nature of the selected solvents, the difference in the solubility parameters of the polymer, solvent and non-solvent. During the coagulation process, the low affinity of DMSO for PES and the high affinity for water lead to increased interaction between the solvent and non-solvent and ensure an optimal coagulation rate during the phase inversion process. Microfiltration membranes in the pore size range of 0.24-0.9 µm were obtained and tested on a laboratory setup created at the institute. In the case of using DMSO as a solvent, high-performance membranes (2184 l/m² h) were obtained, which is 47.16% and 44.13% higher than the productivity of membranes obtained from PES/DMF/water and PES/DMAc/water systems, respectively. The process of PES dissolution was monitored using a polarization interference microscope (Biolar). The particle size, concentration and dispersion index in solutions were studied by dynamic light scattering (Zetasizer Nano Zen3690, Malvern Instruments), the structure and morphology of the membranes were studied by scanning probe (tunneling) microscopy (Certus Standard V, Nano Can Technologies).