Flexible thermally treated 3D PIM-CD molecular sieve membranes exceeding the upper bound line for propylene/propane separation

Jiangtao Liu, Youchang Xiao, Tai-Shung Chung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

Polymers of intrinsic microporosity (PIM) incorporated with beta-cyclodextrin (β-CD) (referred to as PIM-CD) are prepared via nucleophilic substitution copolymerization and then thermally treated at elevated temperatures from 300 to 600 °C. After the decomposition of thermally labile CD, the spaces originally occupied by CD convert to micro-pores and cross-linking points in the polymer matrix. The thermally induced three-dimensional (3D) cross-linking network not only possesses ultra-fine micro-pores and interconnected microvoids but also shows a superior molecular sieve ability for propylene/propane separation. The C3H6/C3H8 selectivity of the thermally treated membranes increases remarkably, about 3 times compared to that of the original untreated membranes. In particular, the PIM-CD membranes thermally treated at 300 or 400 °C are flexible, and they have C3H6/C3H8 separation performance exceeding the upper bound line in both pure and mixed gas tests. As observed from the gas sorption isotherms, membranes with a higher content of CD units have a higher gas sorption capacity. Additionally, the diffusivity selectivity of PIM-CD membranes after thermal treatment increases more quickly than that of the PIM membrane and contributes more to the permeability selectivity.

Original languageEnglish (US)
Pages (from-to)4583-4595
Number of pages13
JournalJournal of Materials Chemistry A
Volume5
Issue number9
DOIs
StatePublished - Jan 1 2017

ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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