| 摘要 |
PURPOSE:To obtain a semipermeable membrane which is stable even after long- term filtration operation by substituting a part of the nitrile type of the semipermeable membrane consisting of an acrylonitirle copolymer with a carboxylic group and/or amide group. CONSTITUTION:A PAN semipermeable membrane of >=50% amt. of acrylonitrile in a polymer can be produced by various known methods. To substitute a part of the nitrile groups of the polymer of such PAN semipermeable membrane with a carboxylic group and/or amide group, an aq. alkali metallic oxide soln. of 1-50wt% concns. is acted wity the PAN semipermeable membrane for 0.08- 10hr at 10-100 deg.C temp., whereby a hydrolysis treatment is carried out. Further, the membrane is subjected to washing and neutralizing in order to remove the alkali metallic hydroxide remaining in the membrane. The semipermeable membrane obtained in this way does not degrade permeation performance even after the filtration operation of a long time, while maintaining the advantage of an acrylonitrile semipermeable membrane. |
