| abstract |
Disclosed is an asymmetric hollow fiber gas separation membrane which is made of a soluble aromatic polyimide consisting of specific repeating units wherein the tetracarboxylic acid component is composed of a diphenylhexafluoropropane structure and a biphenyl structure while the diamine component is composed of a diaminobenzoic acid and one of diaminodibenzothiophene, diaminodibenzothiophene=5,5-dioxide, diaminothioxanthene- 10,10-dione and diaminothioxanthene-9,10,10-trione. |