Relationship between gas separation properties and chemical structure in a series of aromatic polyimides

Kim, T. H.; Koros, William J.; Husk, G. Ronald; O'Brien, Kevin Charles

doi:10.1016/s0376-7388(00)85068-1

Cited by 442 publications

(104 citation statements)

References 22 publications

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“…The effect of (CH 3 CF 3 ) d in the backbones of polyimides on P(H 2 ), P(O 2 ), a(H 2 /N 2 ) and a(O 2 /N 2 ) of polyimides is shown in Fig 3. As (CH 3 CF 3 ) d increased, P(H 2 ) and P(O 2 ) increased, and an abrupt increase is observed when the densities are higher than 11 Â 10 À3 mol cm À3 ; meanwhile, a(H 2 /N 2 ) and a(O 2 /N 2 ) decrease but the latter becomes level after (CH 3 , P(H 2 ) increases 10-fold at 60% loss in a(H 2 /N 2 ), but P(O 2 ) increases 20-fold at 20% loss in a(O 2 /N 2 ). It was suggested that polyimides prepared from 3MPDA or 4MPDA had a high fraction of large holes; 6 therefore a higher (CH 3 CF 3 ) d results in a higher fraction of large holes, leading to lower diffusion selectivity for H 2 /N 2 because of the large difference in molecular size and shape, but it affects moderately the permselectivity for O 2 /N 2 because of their small difference in molecular size and shape.…”

Section: Resultsmentioning

confidence: 99%

Gas permeability and permselectivity of polyimides prepared from phenylenediamines with methyl substitution at the ortho position

Liu¹,

Pan²,

Ding³

et al. 1999

Polym. Int.

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Section: Resultsmentioning

confidence: 99%

Gas permeability and permselectivity of polyimides prepared from phenylenediamines with methyl substitution at the ortho position

Liu¹,

Pan²,

Ding³

et al. 1999

Polym. Int.

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“…For samples containing the dianhydride BKDA, the evolution was smaller, resulting probably from a poorer ability to produce phase segregation. Always, at low PEO contents in the copolymer, the effect of the segregation was very significant, see The permeability and selectivity of pure homopolymers were taken from literature [8,27,28]. Higher phase segregations produced an increase of the permeability to different gases.…”

Section: Gas Transport Propertiesmentioning

confidence: 99%

Advances in the design of co-poly(ether-imide) membranes for CO2 separations. Influence of aromatic rigidity on crystallinity, phase segregation and gas transport

Tena

Marcos‐Fernández

Viuda

et al. 2015

European Polymer Journal

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SummaryIn our previous works, it was observed a clear relationship between the structure and the properties for different copoly(ether-imide)s, besides a good relation was found between SAXS characterization and permeability results. Here, a series of aliphatic aromatic copoly(ether-imide)s, based on an aromatic diamine (ODA), a diamine terminated poly(ethylene oxide) (PEO2000) of a molecular weight of 2000 g/mol and different aromatic dianhydrides (BPDA, BKDA (or BTDA) and PMDA )has been synthesized and characterized.The permeability for O2, N2, CO2 and CH4, increased with the rigidity of the monomers (BKDA < BPDA < PMDA), with the amount of PEO2000 in the copolymers, as well as with the increase in the temperature of treatment of the films. In this case, it was observed that when the proportion of PEO in the copolymer exceeded 50%, the permeability was similar for all samples, and the aromatic portion had no significant influence.Attending to glass transition temperature, Tg, of the aliphatic part, to its melting temperature, Tm, and to its crystallinity, segregation was better for more rigid dianhydrides at lower temperatures of treatment. Higher dianhydride rigidity produced better mechanical properties that were good but decreased a little bit when the percentage of PEO in the samples increased.Good permeselectivity compromises were attained for the CO2/N2 separation .This work gives light to design advanced materials for this separation with the increasing possibilities of controled structure and properties.

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“…Among many polymeric materials, aromatic polyimides consisting of rigid chains and containing bulky and sterically-hindered structures are considered to have great potential as emerging membrane materials [5][6][7]. Extensive research to tailor polyimide chemical structures for better gas separation performance has been carried out in the last two decades [8][9][10][11]. However, structural design attempts to further improve performance have apparently approached a limit as indicated in the trade-off curve describing the relationship between gas permeability and selectivity [12,13].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, cross-linking and carbonization of co-polyimides containing internal acetylene units for gas separation

Xiao

Chung

Guan

et al. 2007

Journal of Membrane Science

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Cross-linkable polyimides containing internal acetylene units have been synthesized by random copolymerization of 6FDA dianhydride, 2,3,5,6-tetramethyl-1,4-phenylenediamine (Durene) and 4,4 ′ -diaminodiphenylacetylene (p-intA) diamine as materials for gas separation. Compared with 6FDA-Durene polyimide, 6FDA-Durene/p-intA co-polyimide shows denser polymer chain packing, which is confirmed by wide-angle X-ray diffraction (WAXD). The thermally treated co-polyimides are insoluble in various solvents and show an increase in T g , indicating the formation of network structures among the polymer chains. Differential scanning calorimetry (DSC) and FT-Raman suggest that cross-linking arises from Diels-Alder cycloaddition between the internally arranged acetylene units along the polymer main chain, resulting in extended conjugated aromatic structures. The thermally cross-linked membranes show enhanced resistance to CO 2 plasticization up to around 5 × 10 6 Pa (700 psi). The rigidified membrane structure provides increased gas selectivity without severely compromising gas permeability. The gas separation performance of carbonized membranes is remarkably superior to those of neat and cross-linked copolyimides because of a large increase in rigidification in the polymer matrix. A Diels-Alder cycloaddition reaction produces a much more rigid and planar conjugated aromatic structure in the polymer chains and results in a higher degree of graphitization during carbonization, which is confirmed by XPS and WAXD. Carbon membranes derived from co-polyimides with more internal acetylene units show much better gas separation performance than those derived from polyimides without internal acetylene units.

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Relationship between gas separation properties and chemical structure in a series of aromatic polyimides

Cited by 442 publications

References 22 publications

Gas permeability and permselectivity of polyimides prepared from phenylenediamines with methyl substitution at the ortho position

Gas permeability and permselectivity of polyimides prepared from phenylenediamines with methyl substitution at the ortho position

Advances in the design of co-poly(ether-imide) membranes for CO2 separations. Influence of aromatic rigidity on crystallinity, phase segregation and gas transport

Synthesis, cross-linking and carbonization of co-polyimides containing internal acetylene units for gas separation

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