Aging phenomenon of 6FDA-polyimide/polyacrylonitrile composite hollow fibers

✍ Scribed by Tai-Shung Chung; E. Ronald Kafchinski

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 418 KB
• Volume: 59
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19960103)59:1<77::aid-app12>3.0.co;2-5

✦ Synopsis

We have observed time-dependent drifts in permeability and selectivity for two types of composite hollow fibers used for air separation. One was PVP [poly(4-vinyl pyridine)]j 6FDA-durene/polyacrylonitrile (PAN) composite hollow fiber, and the other was GFDA-3,5-diaminobenzonitrile/6FDA-durene/PAN composite hollow fiber. Their permeabilities dropped 50 to 70% after 3 to 5 months, while selectivities for 0,/N2 deteriorated slightly with time. A systematic study was carried out to investigate the causes of this creep behavior. Various composite fibers, such as polyimide/Celgard and polyimide siloxane/PAN, were fabricated to simulate the aging process. We conclude that the aging phenomenon observed for these two 6FDA-durene/PAN composite fibers was not due to the structure change of the PAN substrate, but mainly to the densification effect of the GFDA-durene gutter layer on composite fibers.