Fabrication of silica-modified zeolite-based polysulfone nanocomposite membranes: Enhanced thermal, mechanical, and antibacterial properties

Abstract

In this study, polysulfone (PSf) nanocomposite membranes (NCM) have been fabricated by reinforcement with silica-modified zeolite (SiO2-MZ) and polyimide (PI)-SiO2-MZ as inorganic nanocomposite (NC) fillers. To evaluate the improvement in structural, mechanical, and thermal properties of PSf matrix, these nanofillers were incorporated systematically from 1 wt% to 10 wt%. Morphological analysis using transmission electron microscopy and scanning electron microscopy shows better compatibility between PI-SiO2-MZ as the inorganic nanofiller and polymer matrix as compared to SiO2-MZ filler. Physical characteristics of NCMs were studied by Fourier transform infrared spectroscopy and X-ray diffraction analysis. The appropriate ratio of PI-SiO2-MZ as nanofiller in PSf matrix was found through structural analysis. Thermal analysis using differential scanning calorimetry revealed an increase in glass transition temperature ( Tg) with increasing filler concentration. Young’s modulus of PSf/SiO2-MZ NCM (10 wt%) was found to be 1109 MPa, which was improved to 1438 MPa for PSf/PI-SiO2-MZ (10 wt%) NCM. Membrane properties like swelling degree and porosity were also calculated. The degree of swelling of NCMs decreases with decrease in the hydrophilicity of the solvent. Antibacterial properties of NCMs were explored against four bacterial strains namely Klebsella pneumonia, Salmonella typhi, Bacillus subtilis, and Staphylococcus aureus. Good antibacterial activities were obtained for PSf membranes reinforced with PSf/PI-SiO2-MZ NC filler.