Novel spirobifluorene- and dibromospirobifluorene-based polyimides of intrinsic microporosity for gas separation applications

Xiaohua Ma, Octavio Salinas, Eric Litwiller, Ingo Pinnau

Research output: Contribution to journalArticlepeer-review

87 Scopus citations

Abstract

Two series of novel intrinsically microporous polyimides were synthesized from 9,9′-spirobifluorene-2,2′-diamine (SBF) and its bromine-substituted analogue 3,3′-dibromo-9,9′-spirobifluorene-2, 2′-diamine (BSBF) with three different dianhydrides (6FDA, PMDA, and SPDA). All polymers exhibited high molecular weight, good solubility in common organic solvents, and high thermal stability. Bromine-substituted polyimides showed significantly increased gas permeabilities but slightly lower selectivities than the SBF-based polyimides. The CO2 permeability of PMDA-BSBF (693 Barrer) was 3.5 times as high as that of PMDA-SBF (197 Barrer), while its CO2/CH4 selectivity was similar (19 vs 22). Molecular simulations of PMDA-SBF and PMDA-BSBF repeat units indicate that the twist angle between the PMDA and fluorene plane changes from 0 in PMDA-SBF to 77.8 in PMDA-BSBF, which decreases the ability of the polymer to pack efficiently due to severe steric hindrance induced by the bromine side groups. © 2013 American Chemical Society.
Original languageEnglish (US)
Pages (from-to)9618-9624
Number of pages7
JournalMacromolecules
Volume46
Issue number24
DOIs
StatePublished - Dec 3 2013

ASJC Scopus subject areas

  • Materials Chemistry
  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry

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