METHOD FOR PREPARING COMPOSITIONAL POLYMERIC DIFFUSION MEMBRANES AND DIFFUSION MEMBRANES PREPARED BY THIS METHOD Russian patent published in 2003 - IPC

FIELD: chemistry of high-molecular compounds, chemical technology. SUBSTANCE: invention relates to method for preparing compositional polymeric diffusion membranes and can be used in chemical, petrochemical and other branches of industry. Method involves the successive preparing polymeric backing of micro- porous membrane with asymmetric structure by application of aromatic polyamidoimide solution in polar aprotonic solvent on surface of inert material and its immersing into precipitation bath or an aqueous-spirituous solution, washing out and drying. Then method involves shaping skin-layer of diffusion layer on working surface made of one or some layers and the following drying. Membranes represent multiplayer articles comprising microporous backing made of aromatic homo- and/or co-polyamidoimide where diffusion polymeric layer is applied on the working surface - skin-layer. Microporous membrane is made with pore diameter size in skin-layer from 30 to 200 and thickness value from 80 to 250 mcm. Diffusion layer with thickness 1-25 mcm is made of polyfluoroalkyl(meth)acrylate. Method allows preparing membranes with high selectivity for separation of gases mixture being with near kinetic diameter of molecules. Membranes show high effectiveness in the primary separation of non-aqueous mixtures of polar and low-polar organic liquids. Membranes are stable in the water presence. EFFECT: improved preparing method, valuable properties of membranes. 5 cl, 11 tbl, 27 ex