Thermal and Gas Adsorption Properties of Tröger's Base/Diazacyclooctane Hybrid Ladder Polymers

Keiki Inoue, Roman Selyanchyn, Shigenori Fujikawa, Fumitaka Ishiwari, Takanori Fukushima

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


A polymer of intrinsic microporosity (PIM) consisting of Tröger's base (TB) undergoes ring opening of the bicyclic amine upon N-methylation followed by alkaline hydrolysis, resulting in a hybrid ladder polymer that contains diazacyclooctane (DACO) units with tert- and sec-amino groups. The hybrid ladder polymers with various TB/DACO ratios can be prepared depending on the reaction conditions. Here we report a systematic study on the effect of DACO content on the thermal and gas adsorption properties of the hybrid ladder polymer. Using a PIM derived from 2,5-diamino-p-xylene, we prepared hybrid ladder polymers with a DACO content ranging from 19% to 55% while having a similar molecular weight. The thermal stability of the hybrid ladder polymers, evaluated by thermogravimetric analysis, is decreased with the increase in DACO content. Based on gas adsorption measurements, the increase in DACO content results in the decrease in the BET surface area but improves the gas adsorption selectivity for CO2 against N2, likely due to high basicity of the sec-amino group of DACO unit. This result demonstrates that the partial TB-to-DACO conversion of the TB-based PIM may provide a simple but useful strategy to design polymer materials that enable selective CO2 capture and/or separation.

Original languageEnglish
Pages (from-to)824
Number of pages830
Issue number7
Publication statusPublished - Apr 26 2021

All Science Journal Classification (ASJC) codes

  • Biomaterials
  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Materials Chemistry


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