Comparison of membrane properties of sulfonated polysulfone and poly(lactic acid)/polysulfone blends

Unconscious comsumption, increasing population and enviromental pollution with the industrialization has led to contamination of water resources. Nowadays, treatment and reuse of industrial wastewater has became a current issue due to the limited resources. Chemical, petrochemical, environmental, pharmaceuticals, medicine, food, daily food, fruit concentrate, paper, textiles, electronics industry and other industries are located in main areas of treatment processing with membranes. Polysulfone, is used especially at membrane industry, has superior properties such as reproducibility, controlling pore size at membranes, high thermal stability, chemical stability, excellent mechanical performance. PSf based membranes are used at hemodialysis, wastewater treatment and recycling, food and beverage processing and gas separation processing. Besides, polysulfone has some disadvantages such as expensive raw material prices and cost of production due to the high processing temperatures. PSf/ biopolymer blends are developed to reduce these disadvantages. Poly(lactic acid) (PLA) is a preferable biopolymer due to having low cost, low hydrophobicity, good film forming properties and biodegredability. In this study, two methods were tried to increase hydrophilicity of membrane materials. In the first method, PLA/PSf blend were prepared at different ratio to increase hydrophility and decrease cost of membrane material. Blend films were obtained by phase inversion method and solution casting method. These membrane materials of mechanical and membrane properties were investigated. In the second method, PSf was sulfonated with H2SO4, ClSO3H and trimethylsilylchlorosulfonate (TMSCS) reactives to increase hydrophilicity. Thermal and mechanical properties of sulfonated polysulfones were investigated. TMSCS reactive was prefered for sulfonation of PSf according to analysis results. In sulfonation reaction of PSf with TMSCS, hydrophilicity was tried to improve by increasing of sulfonation rate. Sulfonated polysulfones with different rate were investigated mechanical and thermal properties. Film of SPSf having the optimum sulfonation rate was drawn by solution casting method. Membranes were obtained using phase inversion method and investigated membrane and mechanical properties.