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Final Report: High Yield Membrane Reactors
EPA Grant Number: R824727Title: High Yield Membrane Reactors
Investigators: Rezac, Mary
Institution: Georgia Institute of Technology
EPA Project Officer: Karn, Barbara
Project Period: October 1, 1995 through September 30, 1998
Project Amount: $269,999
RFA: Technology for a Sustainable Environment (1995)
Research Category: Pollution Prevention/Sustainable Development
Description:
Objective:This research focuses on the development of novel diacetylene-functionalized polyimides for use as integrally skinned asymmetric membranes. These novel polymers offer easy room-temperature processing. Yet, upon heating, solid-state crosslinking occurs that greatly increases the strength and thermomechanical stability of the materials.
The original milestones set for this research were as follows: (1) evaluation of properties of pyromellitic dianhydride (PMDA)-based polyimide-diacetylene polymers; (2) tailoring of polymer structures to increase material processibility and gas transport rates; (3) formation of high-performance membranes from promising polymers; and (4) evaluation of thermal properties of polymeric materials developed.
Summary/Accomplishments (Outputs/Outcomes):Blends of diacetylene-functionalized polyimides with a non-crosslinkable host polymer resulted in a material that is thermally and chemically stable, easily
processed, flexible, and has outstanding gas-transport properties. These materials meet all of
the requirements set forth in the initial proposal.
- Integrally skinned asymmetric membranes formed from commercially available PEI and l,l-6FDA monomer could be thermally crosslinked to enhance properties. However, the treatment required to achieve crosslinking resulted in a collapse of the microporous structure of the membrane and a degradation in performance. The use of acetylene end-capped monomers in this application was determined to be unacceptable. Rather, future research will focus on the use of oligomers of these diacetylene-containing materials.
- Inclusion of fluorine, oxygen, or ether linkages in the polymer backbone serves to increase polymer processibility and transport rates, while resulting in only a minimal loss in stability.
- Replacement of the aliphatic groups in the polymer backbone with aromatic units results in a marked increase in the thermal stability of the polymer with a slight decrease in its processibility.
- Crosslinking of the diacetylene-functionalized materials produced can proceed through one of three mechanisms, depending upon the chemical structure. The crosslinking route followed influences the resultant properties of the polymer.
- The rate of hydrogen transport through these materials increases as the operating temperature increases. An increase of approximately one order of magnitude is observed over the range of 25-300?C. The ability of the materials to selectively transport hydrogen while excluding hydrocarbons decreases over this temperature range, but remains high (about 10) even at elevated temperatures.
Journal Articles on this Report: 5 Displayed | Download in RIS Format
| Other project views: | All 24 publications | 5 publications in selected types | All 5 journal articles |
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Karangu NT, Rezac ME, Beckham HW. Synthesis and thermal properties of processable polyimides containing diacetylene groups. Polymer Preprints, Division of Polymer Materials, American Chemical Society 1997;76:316-317. |
R824727 (Final) R824725 (Final) |
not available |
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Karangu N, Rezac ME, Beckham HW. Synthesis and characterization of processable polyimides containing diacetylene groups. Chemistry of Materials 1998;10(2):567-573. |
R824727 (Final) |
not available |
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Rezac ME, Bayer B, Sorensen ET, Karangu NT, Beckham HW. Diacetylene-functionalized polyimides for gas separation membranes. Polymer Preprints, Division of Polymer Materials, American Chemical Society 1997;77:285-286. |
R824727 (Final) R824725 (Final) |
not available |
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Rezac ME, Sorensen ET, Beckham HW. Transport properties of crosslinkable polyimide blends. Journal of Membrane Science 1997;136(1-2):249-259 |
R824727 (Final) R824725 (Final) |
not available |
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Rezac ME, Schoberl B. Transport and thermal properties of poly(ether imide) acetylene-terminated monomer blends. Journal of Membrane Science 1999;156(2):211-222 |
R824727 (Final) R824725 (Final) |
not available |
PMDA-based polyimides, polymer structure, solubility, thermal stability, transport properties, siloxane, diacetylene moieties, membrane reactors. , Sustainable Industry/Business, Scientific Discipline, RFA, Technology for Sustainable Environment, Sustainable Environment, cleaner production/pollution prevention, Environmental Chemistry, Economics and Business, membrane reactors, chemical reaction systems, cleaner production, carbon dioxide reaction systems, hydrogeneration, thermochemical stability, polymer design, dehydrogenation reactors, aldehydes, Ethyl benzene, innovative technology, pollution prevention
Progress and Final Reports:
Original Abstract