THERMAL ANNEALING - INDUCED CHANGES IN POLYETHERSULFONE (PES) MEMBRANES: STRUCTURAL, MECHANICAL, AND FLUX CHARACTERIZATION

Polyethersulfone (PES) membranes are known for their outstanding chemical and thermal resistance, making them suitable for various separation processes. However, enhancement in mechanical properties anremaination efficiency remains necessary for achieving optimal membrane functionality. This study investigates the influence of thermal annealing treatment at low temperature of 60°C and 70°C on the morphology, chemical structure, mechanical performance, and pure water flux of PES membranes, compared to none - thermal annealing membranes. Commercial membranes were subjected to thermal treatment for 60 s using a laboratory oven. Characterization techniques included Fourier Transform Infrared Spectroscopy (FT - IR) for functional group analysis, Scanning Electron Microscopy (SEM) for morphological assessment, tensile testing for mechanical evaluation, and dead - end filtration for pure water flux measurement. None - thermal annealing membranes exhibited a tensile strength of 7 MPa, elongation of 43 %, and a water flux of 100 LMH. Annealing at 60°C enhanced pore compactness and uniformity, increasing tensile strength to 9 MPa, elongation to 50 %, and flux to 125 LMH. In contrast, treatment at 70°C further increased water flux to approximately 300 LMH but reduced tensile strength to 6 MPa and elongation to 37 %, indicating a more rigid and brittle structure. FT - IR analysis confirmed no chemical degradation, with enhanced hydrophilic group intensities suggesting improved molecular orientation due to the thermal treatment. The results demonstrate that thermal annealing, particularly at 60°C, can effectively improve PES membrane performance relative to none - thermal annealing membranes while preserving structural integrity, offering a practical approach for advanced membrane - based separation technologies.