Final Report: High Yield Membrane Reactors

EPA Grant Number: R824727
Title: High Yield Membrane Reactors
Investigators: Rezac, Mary
Institution: Georgia Institute of Technology
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 1995 through September 30, 1998
Project Amount: $269,999
RFA: Technology for a Sustainable Environment (1995) Recipients Lists
Research Category: Sustainability , Pollution Prevention/Sustainable Development


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 : 3 Displayed | Download in RIS Format

Other project views: All 24 publications 4 publications in selected types All 3 journal articles
Type Citation Project Document Sources
Journal Article Karangu NT, Rezac ME, Beckham HW. Synthesis and properties of processable polyimides containing diacetylene groups. Chemistry of Materials 1998;10(2):567-573. R824727 (Final)
R824725 (Final)
  • Abstract: ACS-Abstract
  • Journal Article 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)
  • Full-text: ScienceDirect-Full Text PDF
  • Abstract: ScienceDirect-Abstract
  • Journal Article 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)
  • Full-text: ScienceDirect-Full Text HTML
  • Abstract: ScienceDirect-Abstract
  • Other: ScienceDirect-Full Text PDF
  • Supplemental Keywords:

    PMDA-based polyimides, polymer structure, solubility, thermal stability, transport properties, siloxane, diacetylene moieties, membrane reactors., RFA, Scientific Discipline, Sustainable Industry/Business, cleaner production/pollution prevention, Environmental Chemistry, Sustainable Environment, Technology for Sustainable Environment, Economics and Business, carbon dioxide reaction systems, dehydrogenation reactors, thermochemical stability, aldehydes, cleaner production, Ethyl benzene, membrane reactors, chemical reaction systems, innovative technology, pollution prevention, polymer design, separation selectivities

    Progress and Final Reports:

    Original Abstract
  • 1996
  • 1997