METHOD OF MANUFACTURING COMPOSITE POLYMER PERVAPORATION MEMBRANES Russian patent published in 1999 - IPC

FIELD: semipermeable membranes. SUBSTANCE: method includes preparing asymmetric microporous substrate followed by formation of diffusion polymer layer on skin layer of substrate. Substrate is prepared by wet formation technique using 8-15 wt % solutions of aromatic polyamide (formula of elementary unit in claim 1 of invention) with molecular weight 40 to 120 thousand Da in aprotic polar solvent that are applied on smooth surface of inert material and then immersed in precipitation bath. Diffusion layer of poly-N,N,N,N- trimethyl(methacrylouloxyethyl)ammonium salt with quaternization degree 98-100% and molecular weight 1 to 30 million Da is formed on skin layer of substrate when 0.056-0.3% aqueous polymer solution is applied and then dried. EFFECT: enabled combination of high selectivity and productivity when lower aliphatic alcohols are separated from ethers and hydrocarbons over a large range of component concentrations. 8 tbl, 11 ex