METHOD FOR OBTAINING A POLYMER MEMBRANE (OPTIONS) Russian patent published in 2022 - IPC B01D67/00 B01D69/02 C08J5/18 D01F1/10 

FIELD: membrane technology.

SUBSTANCE: group of inventions relates to membrane technologies, namely to the field of obtaining porous polymer flat and hollow fiber membranes. According to all variants of the group of inventions, a polymer solution is pre-prepared and the deposition time is measured by contacting the solution and the precipitator in a diffusion cell between two parallel transparent plates. The method according to the first variant of obtaining a polymer membrane includes the preparation of a polymer solution of the same composition, application of a polymer solution to the substrate, wet molding by immersing the substrate in a sedimentation bath containing a precipitator, washing, drying the membrane or holding in a conditioning bath. The optimal time for the substrate to be in the sedimentation bath, t_{sed. bath}, c, is chosen equal to the deposition time, t_sedim., c), of the polymer layer: .The method for obtaining a polymer membrane according to the second variant includes the preparation of a polymer solution of the same composition, dry-wet molding of the polymer solution through hollow fiber spinners, washing, drying the membrane or holding in a conditioning bath. The pressure above the polymer solution, Δр, Pa, and the air gap above the sedimentation bath, t_{air gap}, m, is chosen so that the ratio between them corresponds to the formula: where the curing time is the t_sedim time of a polymer solution of a certain thickness, c; h_{polym. layer} is the thickness of the polymer layer, m, r_{intern. fiber}, is the inner radius of the fiber, m; C is the coefficient, defined as where R_{out. die} is the outer radius of the die, m; r_{inn. die} is the inner radius of the die, m; η is the coefficient of dynamic viscosity, Pa∙s; is the length of the tube in the annular die, m. The method for obtaining a polymer membrane according to the third option includes the preparation of a polymer solution of the same composition, wet molding of a polymer solution through hollow fiber dies, washing, drying the membrane or holding in a conditioning bath. The pressure above the polymer solution and the length of the path in the precipitation bath are selected according to the above formulas.

EFFECT: group of inventions makes it possible to use small amounts of polymer solution and reduce the number of research stages to determine the optimal molding parameters (pressure above the polymer solution, the length of the path in the precipitation bath or the size of the air gap), the ability to reduce the consumption of expensive reagents.

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