| 摘要 |
<p>PURPOSE:Aromatic polysulfone solution in mixed solvent is added with aqueous electrolyte solution and used for preparing membrane, providing pressure-resistant, high mechanical strength semimembrane free of void on both surfaces. CONSTITUTION:A polysulfone having repeated units of formula is dissolved into a mixed solvent of solvent and nonsolvent; the solvent being polar organic solvent such as N-methyl pyroridone having good polysulfone solubility and containing an aqueous electrolyte such as sodium acetate solution and the nonsolvent for polysulfone being such as dimethyl-sulfoxide that can be mixed with the above polar solvent. The so formed solution is extruded from annular nozzles of hollow fiber making machine in conventional manner, and coagulated form outside surfaces to obtain hollow semipermeable fibers. Such semipermeable fibers have pores of 10 to 100Angstrom diameter gradually increasing toward the center from the outside surface of the fiber, reaching maximum at the center. Voids are not present in the range of 1 to 5mu thick from the surface to the inside, providing water permeability of greater than 1.5m<3>/m<2>.day.atm.</p> |
