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Enhanced ethylene separation and plasticization resistance in polymer membranes incorporating metal–organic framework nanocrystals


The implementation of membrane-based separations in the petrochemical industry has the potential to reduce energy consumption significantly relative to conventional separation processes1. Achieving this goal, however, requires the development of new membrane materials with greater selectivity, permeability and stability than available at present. Here, we report composite materials consisting of nanocrystals of metal–organic frameworks dispersed within a high-performance polyimide, which can exhibit enhanced selectivity for ethylene over ethane, greater ethylene permeability and improved membrane stability. Our results suggest that framework–polymer interactions reduce chain mobility of the polymer while simultaneously boosting membrane separation performance. The increased stability, or plasticization resistance, is expected to improve membrane utility under real process conditions for petrochemical separations and natural gas purification. Furthermore, this approach can be broadly applied to numerous polymers that encounter aggressive environments, potentially making gas separations possible that were previously inaccessible to membranes.

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Figure 1: Physical and adsorptive properties for M2(dobdc) nanocrystals.
Figure 2: Ethylene/ethane separation performance for M2(dobdc)/6FDA-DAM membranes.
Figure 3: Cross-sectional images of M2(dobdc)/6FDA-DAM membranes.
Figure 4: Enhanced membrane stability, reduction in plasticization and high mixed-gas selectivities.

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This research was supported through the Center for Gas Separations Relevant to Clean Energy Technologies, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under Award DE-SC0001015. We thank J. Mason for helpful discussions. We also thank the NSF for providing graduate fellowship support for J.E.B.

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Authors and Affiliations



J.E.B. and J.R.L. formulated the project. J.E.B. synthesized nanocrystals and fabricated membranes. Z.P.S. contributed valuable theoretical insights, synthesized 6FDA-DAM, and assisted in construction of permeation equipment. J.E.B. collected all powder diffraction, dynamic light scattering, scanning electron microscopy, Soxhlet extractions, gas adsorption, and gas permeation data. T.L. performed transmission electron microscopy imaging. J.E.B. and J.R.L. wrote the paper, and all authors contributed to revising the paper.

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Correspondence to Jeffrey R. Long.

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Bachman, J., Smith, Z., Li, T. et al. Enhanced ethylene separation and plasticization resistance in polymer membranes incorporating metal–organic framework nanocrystals. Nature Mater 15, 845–849 (2016).

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