| abstract |
PURPOSE: To obtain a gas separation membrane excellent in oxygen permeability, chemical resistance and mechanical strength, by forming the same from a polyurea/silicone copolymer having a polysiloxane structure into the main chain of the polyurea thereof. n CONSTITUTION: A gas separation membrane has a structural unit shown by a formula and, for example, prepared as mentioned hereinbelow. That is, in a solution of bis(γ-aminopropyl)tetramethyldisloxane in N-methyl-2-pyrrolidone, a solution of diphenylmethane diisocyanate in a solvent mixture consisting of N-methyl-2-pyrrolidone and methyl isobutyl ketone is dripped in a small increment and the resulting mixture is reacted under heating. The reaction mixture is thrown into a large amount of water to precipitate a copolymer. After a 5wt% solution of this copolymer in N-methyl-2-pyrrolidone is cast on a tin plated plate, the formed film is heated at 20°C for 4hr and further heated at 150°C for 1hr to evaporate the solvent and a homegeneous copolymer membrane is obtained. This membrane has coefficient of O 2 -permeation of 3.1×10 -10 cm 2 . cm/cm 2 .sec cm Hg and coefficent of N 2 -permeation of 7.7×10 -11 cm 2 .cm/cm 2 sec cm Hg. n COPYRIGHT: (C)1984,JPO&Japio |