| 摘要 |
PURPOSE:To dry the membrane while keeping the shrinkage percentage of the membrane low by treating a hydrophilicity-provided polymeric membrane formed by a dry and wet method with a poor solvent for a polymer compatible with hydrocarbons and water and then drying the membrane. CONSTITUTION:Water or an aq. soln. is used as the gel-forming bath and a wet hydrophilicity-provided polymeric ultrafilter membrane formed by a dry and wet process is dried in this method. The membrane is firstly pretreated with a poor solvent for the membrane which is compatible with 5-8C saturated hydrocarbons and water. Lower alcohols such as methanol and ethanol are used as the solvent. Then the membrane is treated with the above-mentioned saturated hydrocarbon having a high saturated vapor pressure and the solvent in the membrane is replaced. As the solvent, n-hexane and cyclohexane are preferably used and the membrane is immersed in the solvent at 10-30 deg.C for 10-30hr and treated. The membrane is finally dried at 30-50 deg.C for 10-30hr. |
