(814a) Polyimide Membranes With High Fractional Free Volume for Gas Separations

Polyimide Membranes with High Fractional Free volume for Gas Separations

 Jennifer Wiegand (jwiegan2@nd.edu), Ruilan Guo (rguo@nd.edu)

Department of Chemical and Biomolecular Engineering, University of Notre Dame

Notre Dame, IN 46556-5637

As being realized, the biggest challenge for these polymeric gas separation membranes is the trade-off relationship between gas permeability and selectivity defining the so-called “upper bound”.  Over the years, substantial research efforts have been directed to expanding the polymeric membrane performance envelope via designing novel polymer materials. Particularly, it has been demonstrated that polymer membranes featuring high fractional free volume, such as thermally rearranged (TR) polymers in our previous studies^1-4 and polymers of intrinsic microporosity (PIMs)^5-7, provide unprecedented combination of high gas permeability and high selectivity.  Here we report a new series of high performance polyimide membranes with high fractional free volume as well as tunable microcavities that have great potential for fast and selective transport of small molecules.  These novel polyimides were designed and derived via incorporating a unique set of triptycene components in their backbone structures, which are bulky, three-dimensional, shape persistent units and possess rich structural hierarchy and versatile chemistry possibilities allowing unique chain arrangement and organization mechanism to induce hierarchically controlled architectures in the resulting membranes.  Molecular design, synthesis and characterization of these new polyimides will be presented with a focus on how to incorporate and tune the architecture of the microcavities via introduction of side bulky groups and/or adjusting the interlinking geometry.  Preliminary pure gas permeation data (with H₂, N₂, O₂, CO₂, and CH₄) will be presented for these new polyimide membranes.  The correlation between microscopic structures (primary backbone structure, chain packing efficiency, fractional free volume, etc.) of the triptycene-containing polyimides with macroscopic membrane gas transport properties will be discussed.

References:

1.         R. Guo, D. F. Sanders, Z. P. Smith, B. D. Freeman, D. R. Paul and J. E. McGrath, Journal of Materials Chemistry A, 2013, 1, 6063-6072.

2.         R. Guo, D. F. Sanders, Z. P. Smith, B. D. Freeman, D. R. Paul and J. E. McGrath, Journal of Materials Chemistry A, 2013, 1, 262-272.

3.         D. F. Sanders, Z. P. Smith, C. P. Ribeiro, R. Guo, J. E. McGrath, D. R. Paul and B. D. Freeman, J Membrane Sci, 2012, 409-410, 232-241.

4.         Z. P. Smith, D. F. Sanders, C. P. Ribeiro, R. Guo, B. D. Freeman, D. R. Paul, J. E. McGrath and S. Swinnea, J Membrane Sci, 2012, 415-416, 558-567.

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6.         P. M. Budd, B. S. Ghanem, S. Makhseed, N. B. McKeown, K. J. Msayib and C. E. Tattershall, Chem Commun, 2004, 230-231.

7.         P. M. Budd, K. J. Msayib, C. E. Tattershall, B. S. Ghanem, K. J. Reynolds, N. B. McKeown and D. Fritsch, Journal of Membrane Science, 2005, 251, 263-269.