Preparation of selectively permeable membrane for treating organic liquid

Abstract

Abstract PURPOSE:To provide the titled membrane excellent in solvent permeable rate and selective permeability, by a method wherein a substrate is coated with a membrane stock solution containing a polyimide and a polyamide or a polyamideimide, which is formed into membranes by coagulating with water, and then water in the membranes is replaced with a substituting solvent. CONSTITUTION:A dope solvent is used to dissolve either a polyimide mainly composed of a repeating unit of formula I (R<1>: divalent organie gp.) and a polyamide mainly composed of a repeating unit of formula II (R<2>, R<3>: divalent aromatic gp.), or a polyamideimide mainly composed of a repeating units of formula IIIa (R<4>: divalent aromatic gp.) or, in some case, formula IIIb (R<5>, R<6>: divalent aromatic gp.). The obtained dope is coated on a substrate, which is immersed in a coagulant solution consisting of water to cause the polymer to be coagulated into membranes. Then, water in the membranes is replaced with an organic solvent which does not dissolve the polymer and is compatible with water and any organic solvent present in the solution mixture. The obtained membranes are used for treating a liquid mixture mainly consisting of a water-incompatible organic solvent.

Inventors

• 👤 Noritaka Kazuse
• 👤 Akio Iwama
• 👤 Hiroshi Iwabori

Bibliographic Details