Tuning the Gas Selectivity of Tröger's Base Polyimide Membranes by Using Carboxylic Acid and Tertiary Base Interactions

Zhenggong Wang; Ali Pournaghshband Isfahani; Kazuki Wakimoto; Binod Babu Shrestha; Daisuke Yamaguchi; Behnam Ghalei; Easan Sivaniah

doi:10.1002/cssc.201801002

Tuning the Gas Selectivity of Tröger's Base Polyimide Membranes by Using Carboxylic Acid and Tertiary Base Interactions

ChemSusChem. 2018 Aug 22;11(16):2744-2751. doi: 10.1002/cssc.201801002. Epub 2018 Jul 10.

Authors

Zhenggong Wang¹, Ali Pournaghshband Isfahani¹, Kazuki Wakimoto^{1

2}, Binod Babu Shrestha¹, Daisuke Yamaguchi^{1

3}, Behnam Ghalei^{1

3}, Easan Sivaniah^{1

3}

Affiliations

¹ Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, 606-8501, Kyoto, Japan.
² Graduate School of Energy Science, Kyoto University, Kyoto, 606-8501, Japan.
³ Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 615-8510, Japan.

PMID: 29808569
DOI: 10.1002/cssc.201801002

Abstract

Polyimide-based materials provide attractive chemistries for the development of gas-separation membranes. Modification of inter- and intra-chain interactions is a route to improve the separation performance. In this work, copolyimides with Tröger's base (TB) monomers are designed and synthesized. In particular, a series of copolyimides is synthesized with different contents of carboxylic acid groups (0-50 wt %) to alter the inter- and intra-chain interactions and enhance the basicity of the TB-polyimides. A detailed thermal and structural analysis is provided for the new copolyimides. Gas permeation data reveal a tunable trend in separation performance with increasing carboxylic acid group content. Importantly, this is one of the few examples of copolyimide membranes materials that show enhanced plasticization resistance to high-pressure gas feeds through physical cross-linking.

Keywords: carboxylic acids; gas separation; membranes; plasticization; polyimide.