• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.183-186
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• 2004

Nano particles-containing CMS membranes were prepared by pyrolysis of polyimides dispersed uniformly with precursors and their gas separation performances were examined, to elucidate the permeation mechanism and to further improve the gas separation performance. Consequently, it was suggested that the separation performance could be controlled by doping nano-particles in the CMS membranes, and that optimization of various factors, such as the size, content, and dispersion state of the nano particles would contribute for further improvement of the gas separation performance.

• Korean Membrane Journal
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• v.4 no.1
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• pp.25-35
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• 2002

The gas permeation properties have been studied on carbon molecular sieve (CMS) membranes prepared by pyrolysis of P84 polyimide under various conditions. P84 polyimide shows high permselectivities (O$_2$/N$_2$= 9.17 and CO$_2$/N$_2$= 35) for various gas pairs and has a good processibility because it is easily soluble in high polar solvents such as N-methylpyrrolidinone (NMP), dimethylformamide (DMF), and N,N-dimethylacetamide (DMAc). After pyrolysis under Ar flow, the change in the heating rate was found to affect the gas permeation properties to some extent. The permeabilities of the selected gases were shown to be in the order He ＞ CO$_2$＞ O$_2$＞ N$_2$for all the CMS membranes, whose order was in accordance with the order of kinetic gas diameters. It also revealed that the pyrolysis temperature considerably influenced the gas permeation properties of the CMS membranes derived from P84 polyimide. The CMS membranes pyrolized at 700$\^{C}$ temperature exhibited the highest permeability with relatively targe loss in permselectivity. This means that the pyrolysis temperature should be varied in accordance with target gases to be separated.

• Membrane Journal
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• v.11 no.1
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• pp.1-13
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• 2001

• Proceedings of the Membrane Society of Korea Conference
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• 2005.11a
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• pp.39-47
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• 2005

• Membrane Journal
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• v.7 no.1
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• pp.15-21
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• 1997

Carbon molecular sieve (CMS) membranes were synthesized by the pyrolysis of polymeric precursors. The CMS materials had oxygen-nitrogen selectivities much higher than those observed for the polymeric precursors. Typically molecular sieving materials have diffusion selectivities much higher than polymeric materials. This has been identified as a result of higher entropic selectivity of the molecular sieving materials. A study of the development of molecular sieving properties as the polymeric precursor is pyrolyzed into a CMS material will offer us an insight into polymeric molecular structures needed for enhanced entropic selectivity membrane materials.

• Proceedings of the Membrane Society of Korea Conference
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• 2001.05a
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• pp.59-62
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• 2001

• Membrane Journal
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• v.30 no.4
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• pp.260-268
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• 2020

Mixed-matrix carbon molecular sieve membranes containing conventional and hierarchically structured 5A were synthesized for application in oxygen (O₂)/nitrogen (N₂) separation. In general, incorporating 5A fillers into porous carbon matrices dramatically increased the permeability of the membrane with a marginal decrease in selectivity, resulting in very attractive O₂/N₂ separation performances. Hierarchical zeolite 5A, which contains both microporous and mesoporous domains, improved the separation performance further, indicating that the mesopores in the zeolite can serve as an additional path for rapid gas diffusion without sacrificing O₂/N₂ selectivity substantially. This facile strategy successfully and cost-effectively pushed the performance close to the Robeson upper bound. It produced high performance membranes based on Matrimid^® 5218 polyimide and zeolite 5A, which are inexpensive commercial products.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.11a
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• pp.169-171
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• 2004

• Proceedings of the Membrane Society of Korea Conference
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• 2002.11a
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• pp.88-92
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• 2002

No Abstract, See Full Text

• Proceedings of the Membrane Society of Korea Conference
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• 2002.05a
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• pp.77-80
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• 2002

No Abstract, See Full-text