Preparation and formation mechanism of polyethersulfone/ sulfonated polyethersulfone ultrafiltration membranes

摘要

Membrane fouling and insufficient mechanical strength restrict the application of the ultrafiltration (UF) membrane in the water treatment field. Consequently, hydrophilic modification and improvement of the mechanial strength of the membrane are vitally required for the improvement of the performance. Among all the modification methods, blending sulfonated polyethersulfone (SPES) into polyethersulfone (P ES) membrane is one of the popular methods, due to the hydrophilic and negatively-charged sulfonate groups on SPES chains. Due to the softness of hydrophilic segments, the blend membrane exhibits the low mechanical strength. The blending additive with high molecular weight would significantly enhance the kinetic hindrance during phase separation process, leading to the suppression of macrovoids formation in the cross section, which will increase the mechanical strength of the blend membranes 1, 2) . It was found that the possible hydrogen bonding between SPES – Dimethylacetamide (DMAc) had a great influence on the formation of the membrane structure. In this research, the structures and properties of the blend membranes, and the formation mechanism were investigated.