| Polysulfone(PSf),with its excellent physical and chemical properties,has become one of the most widely used membrane materials in the field of membrane separation.In order to improve the permeability of the PSf membrane,the most commonly method is to add water-soluble macromolecules or inorganic ion additives.Although it can improve the permeability and separation properties of the membrane,the tensile properties of the modified membrane have not been significantly improved.At the same time,water-soluble additives will be slowly dissolved during the operation of membrane module,which does not meet the requirements of the materials in contact with water.Therefore,it is of great significance to improve the mechanical properties of PSf matrix and simultaneously improve its permeability and separation performance by mixing water-insoluble rigid macromolecules in PSf matrix.The PMIA/PSf/DMAc blending casting solution was successfully prepared and the PMIA/PSf blend membrane was prepared by the non-solvent phase separation method.First,it is determined that the best addition quantity of cosolvent(CaC12)is 3%.The effect of PMIA/PSf blending ratio and polymer concentration on the viscosity of casting solution,structure and properties of the blend membrane were investigated.The results showed that the addition of PMIA significantly increased the fracture strength,elongation at break,porosity of the blend membrane,significantly improved the hydrophilicity and the pure water flux,but the rejection of BSA decreased.On the basis of the anlysis of the flat membrane,the PMIA/PSf blend hollow fiber membrane was successfully prepared.The effect of coagulation bath temperature,air gap,PMIA/PSf blending ratio and polymer concentration on the morphology and properties of hollow fiber membrane were investigated.The results showed that:with the increase of coagulation bath temperature,large tear hole structure appeared,the breaking strength and elongation at break decreased,and the porosity increased slightly.The pure water-flux increased first and then decreased.BSA rejection first decreased and then increased.With the increase of air gap,the porosity of membrane increased,and the tensile properties of hollow fiber membrane gradually declined.Pure water flux first increased and then decreased.BSA rejection first decreased and then increased.When the content of PMIA increased gradually,the pore structure of membrane cross section gradually disappeared,and the porosity increased.The elongation at break increased and then decreased.The pure water flux increased and the BSA rejection decreased.When the polymer concentration increased from 18%to 24%,the membrane structure gradually became denser,the tensile properties increased obviously,the pure water flux decreased and the BSA rejection increased. |
