ULTRA-FILTRATING HEAT AND CHEMICAL RESISTANT POLYIMIDE MEMBRANE AND METHOD OF ITS

摘要

FIELD: technological processes. ^ SUBSTANCE: invention concerns obtaining ultrafiltration ultraporous polyimide membranes resistant to heat and chemicals and can be applied in membrane technologies, particularly at temperatures over 200C and in aggressive media. Membrane has a form of porous film or hollow fiber with anisotropic structure, including selective layer and substrate. Ultraporous selective surface layer with 70-800 A0 pore size and 0.1-10 mcm thickness consists of insoluble rigid-chain aromatic (co)polyimide based on aromatic tetracarboxylic acid dianhydride and aromatic diamine, and is placed on microporous substrate made of the same polymer of 50-250 mcm thickness. The membrane features water permeability Q=(2-500)10-4 cm/sec under atmospheric pressure and rated molecular detention weight ML=(5-500)103 g/mol. Method of obtaining the membrane involves preparation of 10-15% forming solution of (co)polyamide acid based on aromatic tetracarboxylic acid dianhydride and aromatic diamine in amide solvent; stirring; decontamination. Solution of polyimidoamide acid imidised by 20-40% is poured through spinneret with adjustable clearance onto the forming plate. Then the plate is submerged into water or water-alcohol settlement tank. Formed membrane is held in 20-60% high-boiling industrial oil solution in organic solvent to fill membrane pores with oil, dried and heated to 150-200C at temperature growth rate of 10 degrees per minute till complete (co)polyimidoamide acid imidisation. Membrane operation temperature reaches 300-400C. Membranes preserve their properties in aggressive media and organic solvents. ^ EFFECT: obtaining of ultrafiltration ultraporous polyimide membranes resistant to heat and chemicals. ^ 15 cl, 21 ex