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Title: Increasing M 2(dobdc) Loading in Selective Mixed-Matrix Membranes: A Rubber Toughening Approach

Mixed-matrix membranes (MMMs) were formed by incorporating M 2(dobdc) (M = Mg, Ni; dobdc 4– = 2,5-dioxido-1,4-benzenedicarboxylate) metal–organic framework (MOF) nanoparticles in a series of poly(ether-imide) copolymers. Addition of the MOF nanoparticles improved the permeability of H 2, N 2, CH 4, and CO 2 relative to the pure copolymer by increasing gas solubility and, in most cases, diffusivity. More limited improvements in diffusivity were observed for the more strongly adsorbing gases. Because of such transport considerations, improvements in permeability and selectivity were most pronounced for H 2/CH 4 and H 2/N 2 separations. Incorporation of a greater ether content within the copolymers led to the formation of defect-free MMMs by physically sealing polymer–MOF interfacial defects, allowing higher MOF loadings to be achieved. For Mg 2(dobdc), selective, defect-free films could be formed with loadings of up to 51 wt %. However, at these high loadings, films became weak and brittle. The mechanical properties of the composite materials were therefore quantified by tensile tests and compared to those of the neat polymers used commercially for membrane film formation. High contents of flexible ether units and small MOF nanoparticle sizes were found to be necessary to form strong and ductile MMMs, althoughmore » clear trade-offs exist between transport performance, MOF loading, and mechanical properties. In conclusion, these trade-offs are critically examined to evaluate the current limitations and potential benefits to forming M 2(dobdc) MMMs using this rubber toughening approach.« less
Authors:
 [1] ; ORCiD logo [2] ;  [3] ;  [4] ; ORCiD logo [5] ; ORCiD logo [6] ;  [5] ; ORCiD logo [7] ; ORCiD logo [8]
  1. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Chemical Engineering
  2. Univ. of California, Berkeley, CA (United States). Dept. of Chemical and Biomolecular Engineering
  3. Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Engineering; ShanghaiTech Univ., Shanghai (China). School of Physical Science and Technology
  4. Univ. of New South Wales, Sydney, NSW (Australia). School of Mechanical and Manufacturing Engineering
  5. National Energy Technology Lab. (NETL), Pittsburgh, PA (United States)
  6. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Engineering
  7. Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Engineering; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
  8. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Univ. of California, Berkeley, CA (United States). Dept. of Chemical and Biomolecular Engineering
Publication Date:
Grant/Contract Number:
SC0001015; FE0004000
Type:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 30; Journal Issue: 5; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Research Org:
National Energy Technology Lab. (NETL), Pittsburgh, PA, and Morgantown, WV (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1455423