METHOD OF PRODUCING POROUS MEMBRANE BASED ON POLYTETRAFLUOROETHYLENE Russian patent published in 2024 - IPC B01D67/00 B01D71/36 

FIELD: various technological processes.

SUBSTANCE: invention relates to production of semipermeable membranes for separation processes. Disclosed is a method of producing porous membranes based on polytetrafluoroethylene by preparing a spinning solution containing the following in wt.%: 12.17–12.21 aqueous 5% polyethylene oxide solution, 76.05–76.34 fluoroplastic aqueous suspension of polytetrafluoroethylene “Ф-4Д”, 11.40–11.45 of distilled water and 0.02–0.38 of potassium chloride, when mixing components in an ultrasonic bath filled with distilled water, with an operating frequency of 35 kHz at temperature of 40 °C for 1 hour, and then in a rotating mill for 8 hours, then electrospinning is carried out at high-voltage source voltage of 25 kV at a spinning solution feed rate of 1.5 ml/h, injector displacement speed 30 mm/s and at distance from injector to assembly manifold 90 cm and injector diameter 0.7 mm with subsequent heat treatment in a muffle furnace at a heating rate of 1.7 °C per minute up to 350 °C, at which it is held for 10 minutes, after cooling in air to room temperature, the semi-finished product is placed in a fluoroplastic cup with perfluorodecalin with concentration of 99.2 wt.%, cup is installed in a steel reactor, which is sealed and evacuated to pressure of 10 kPa and treated with a fluorine-nitrogen mixture with a fluorine concentration of 20 vol.% to pressure of 4 atm. for 3 hours, then the semi-finished product is removed, washed with ethanol and dried in a vacuum oven for 2 hours at temperature of 80 °C and pressure of 20 kPa.

EFFECT: reducing the number of defects in the membrane structure, possibility of controlling the size of the fibres forming the membrane, and reduced time for electrospinning of semi-finished product.

1 cl, 5 dwg, 1 tbl, 5 ex