Intrinsically Microporous Polymer Membranes for High Performance Gas Separation

Handle URI:
http://hdl.handle.net/10754/336029
Title:
Intrinsically Microporous Polymer Membranes for High Performance Gas Separation
Authors:
Swaidan, Raja ( 0000-0002-9296-6501 )
Abstract:
This dissertation addresses the rational design of intrinsically microporous solutionprocessable polyimides and ladder polymers for highly permeable and highly selective gas transport in cornerstone applications of membrane-based gas separation – that is, air enrichment, hydrogen recovery and natural gas sweetening. By virtue of rigid and contorted chains that pack inefficiently in the solid state, polymers of intrinsic microporosity (PIMs) have the potential to unite the solution-processability, mechanical flexibility and organic tunability of commercially relevant polymers with the microporosity characteristics of porous crystalline materials. The performance enhancements of PIMs over conventional low-free-volume polymers have been primarily permeability-driven, compromising the selectivity essential to commercial viability. An approach to unite high permeability with high selectivity for performance transcending the state-of-the-art in air and hydrogen separations was demonstrated via a fused-ring integration of a three-dimensional, shape persistent triptycene moiety optimally substituted with short, branched isopropyl chains at the 9,10-bridgeheads into a highly inflexible backbone. The resulting polymers exhibited selectivities (i.e., O2/N2, H2/N2, H2/CH4) similar to or higher than commercial materials matched with permeabilities up to three hundred times higher. However, the intra-chain rigidity central to such conventional PIM-design principles was not a singular solution to suppression of CO2-induced plasticization in CO2/CH4 mixedgas separations. Plasticization diminishes the sieving capacity of the membrane, resulting in costly hydrocarbon losses that have significantly limited the commercialization of new polymers. Unexpectedly, the most permeable and selective PIMs designed for air and hydrogen separations strongly plasticized in 50:50 CO2/CH4 mixtures, enduring up to three-fold increases in mixed-gas CH4 permeability by 30 bar and strong drops in selectivity. Instead, a paradigm shift emphasizing inter-chain rigidity was demonstrated for the PIM-type polyimides via introduction of a flexible diamine functionalized with hydroxyl groups. Intra-chain flexibility may permit short-range coplanarization of backbone segments which facilitates inter-chain interactions likely comprising charge transfer complexes over the N-phenyl imide bond and hydrogen bonding. Relative to commercial cellulose acetate membranes at a representative 10 bar CO2 partial pressure, the resulting polyimide exhibited two-fold increases in mixed-gas CO2/CH4 selectivity (~50) concurrent with nearly 10-fold higher CO2 gas permeability. Similar design principles were drawn for ladder polymers.
Advisors:
Pinnau, Ingo ( 0000-0003-3040-9088 )
Committee Member:
Eddaoudi, Mohamed ( 0000-0003-1916-9837 ) ; Lai, Zhiping ( 0000-0001-9555-6009 ) ; Peinemann, Klaus-Viktor ( 0000-0003-0309-9598 )
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Program:
Chemical and Biological Engineering
Issue Date:
Nov-2014
Type:
Dissertation
Appears in Collections:
Dissertations; Physical Sciences and Engineering (PSE) Division; Chemical and Biological Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.advisorPinnau, Ingoen
dc.contributor.authorSwaidan, Rajaen
dc.date.accessioned2014-11-24T08:06:10Z-
dc.date.available2014-11-24T08:06:10Z-
dc.date.issued2014-11en
dc.identifier.urihttp://hdl.handle.net/10754/336029en
dc.description.abstractThis dissertation addresses the rational design of intrinsically microporous solutionprocessable polyimides and ladder polymers for highly permeable and highly selective gas transport in cornerstone applications of membrane-based gas separation – that is, air enrichment, hydrogen recovery and natural gas sweetening. By virtue of rigid and contorted chains that pack inefficiently in the solid state, polymers of intrinsic microporosity (PIMs) have the potential to unite the solution-processability, mechanical flexibility and organic tunability of commercially relevant polymers with the microporosity characteristics of porous crystalline materials. The performance enhancements of PIMs over conventional low-free-volume polymers have been primarily permeability-driven, compromising the selectivity essential to commercial viability. An approach to unite high permeability with high selectivity for performance transcending the state-of-the-art in air and hydrogen separations was demonstrated via a fused-ring integration of a three-dimensional, shape persistent triptycene moiety optimally substituted with short, branched isopropyl chains at the 9,10-bridgeheads into a highly inflexible backbone. The resulting polymers exhibited selectivities (i.e., O2/N2, H2/N2, H2/CH4) similar to or higher than commercial materials matched with permeabilities up to three hundred times higher. However, the intra-chain rigidity central to such conventional PIM-design principles was not a singular solution to suppression of CO2-induced plasticization in CO2/CH4 mixedgas separations. Plasticization diminishes the sieving capacity of the membrane, resulting in costly hydrocarbon losses that have significantly limited the commercialization of new polymers. Unexpectedly, the most permeable and selective PIMs designed for air and hydrogen separations strongly plasticized in 50:50 CO2/CH4 mixtures, enduring up to three-fold increases in mixed-gas CH4 permeability by 30 bar and strong drops in selectivity. Instead, a paradigm shift emphasizing inter-chain rigidity was demonstrated for the PIM-type polyimides via introduction of a flexible diamine functionalized with hydroxyl groups. Intra-chain flexibility may permit short-range coplanarization of backbone segments which facilitates inter-chain interactions likely comprising charge transfer complexes over the N-phenyl imide bond and hydrogen bonding. Relative to commercial cellulose acetate membranes at a representative 10 bar CO2 partial pressure, the resulting polyimide exhibited two-fold increases in mixed-gas CO2/CH4 selectivity (~50) concurrent with nearly 10-fold higher CO2 gas permeability. Similar design principles were drawn for ladder polymers.en
dc.language.isoenen
dc.subjectPolymeren
dc.subjectGas Separationen
dc.subjectMembranesen
dc.subjectNatural Gasen
dc.subjectAir and Hydrogenen
dc.subjectTriptyceneen
dc.titleIntrinsically Microporous Polymer Membranes for High Performance Gas Separationen
dc.typeDissertationen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen_GB
dc.contributor.committeememberEddaoudi, Mohameden
dc.contributor.committeememberLai, Zhipingen
dc.contributor.committeememberPeinemann, Klaus-Viktoren
thesis.degree.disciplineChemical and Biological Engineeringen
thesis.degree.nameDoctor of Philosophyen
dc.person.id101783en
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