Answers are grounded in this paper and cite their sources.
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)]/6FDA-durene/polyacrylonitrile (PAN) composite hollow fiber, and the other was 6FDA-3,5-diaminobenzonitrile/6FDA-durene/PAN composite hollow fiber. Their permeabilities dropped 50 to 70% after 3 to 5 months, while selectivities for O2N2 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 6FDA-durene gutter layer on composite fibers.
No takes yet. Share an insight, caveat, or question.
Chung et al. (1996) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: