The gas separation effects of annealing polyimide-organosilicate hybrid membranes

C. Hibshman, C. J. Cornelius, E. Marand

Research output: Contribution to journalArticlepeer-review

117 Scopus citations

Abstract

Polyimide-organosilicate hybrid membranes were subjected to annealing to enhance gas separation performance. These membranes consisted of organosilicate domains covalently bonded to a 6FDA-6FpDA-DABA polyimide using partially hydrolyzed tetramethoxysilane (TMOS), methyltrimethoxysilane (MTMOS) or phenyltrimethoxysilane (PTMOS). The transport properties of the hybrid membranes were evaluated using pure gases (He, O2, N2, CH4, CO2) at 35°C and a feed pressure of 4atm. The permeability for most of the membranes increased 200-500% after the annealing process while the permselectivity dropped anywhere from 0 to 50%. The exceptions were the 6FDA-6FpDA-DABA-25 22.5% TMOS and MTMOS hybrid membranes, both of which exhibited increases in the CO2 permeability and CO2-CH4 permselectivity. The transport data was compared to Robeson's 1991 "upper bound" and exceeded the boundary in some cases. The increase in permeation was attributed to changes in the free volume distribution and enhanced local segmental mobility of the chain ends resulting from the removal of sol-gel condensation and polymer degradation byproducts.

Original languageEnglish (US)
Pages (from-to)25-40
Number of pages16
JournalJournal of Membrane Science
Volume211
Issue number1
DOIs
StatePublished - Jan 1 2003

Keywords

  • Composite membranes
  • Gas separations
  • Inorganic membranes
  • Organosilicate
  • Polyimide

ASJC Scopus subject areas

  • Biochemistry
  • Materials Science(all)
  • Physical and Theoretical Chemistry
  • Filtration and Separation

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