| Polyether sulfone (PES), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF) are common materials in the development of ultrafiltration membranes. However, because of the hydrophobic nature, these membranes may induce proteins or microbes (including bacteria and viruses) adhesion and the performance of the membranes become worse in practice. In this paper, different approaches are applied to improve the hydrophilicity and the performances of ultrafiltration membranes.In the first part of this paper, our strategy was using sodium persulfate to crosslink PVP in the membranes and investigate the properties of both the crosslinked membranes and not crosslinked ones. The results showed that the crosslinked membranes had higher pure water flux. Meanwhile, the rejecton ratio and mechanical properties were slightly decreased.In order to further improve the hydrophilicity of the membbranes, the second part of this paper researched on zewitterionic PAN ultrafiltration membranes by grafting with different kinds of nature a-amino acids. First of all, glycidyl methacrylate was polymerized to prepare polymer PGMA and then PAN/PGMA ultrafiltration membranes were prepared via phase inversion method. Then, different kinds of nature a-amino acids were grafted onto the PAN membranes to form zewitterionic surfaces. After that, a variety of analysis and testing methods were used to investigate the chemical and physical properties of the zewitterionic PAN ultrafiltration membranes. The results showed that PAN membranes grafted with nature α-amino acids had better hydrophilicity and antifouling property.Finally, to explore the industrial application of zewitterionic ultrafiltration membranes, the third and fourth parts researched on zewitterionic PES and PVDF hollow fiber membranes respectively. Both of the PES/PGMA and PVDF/PGMA ultrafiltration hollow fiber membranes were prepared and grafted with different kinds of nature a-amino acids. Afterwards, a series of ways were used to research on the properties of the hollow fiber membranes. The results indicated that zewitterionic hollow fiber membranes also had excellent hydrophilicity and antifouling property. |
