Synthesis, characterization, and gas transport properties of novel iptycene-based poly[bis(benzimidazobenzisoquinolinones)]

Two novel iptycene-based tetramine monomers were successfully synthesized by nucleophilic aromatic substitution of triptycene-1,4-diol and pentiptycene-6,13-diol with 5-chloro-2-nitro-aniline, followed by reduction, respectively. These monomers were polymerized with 4,4-binaphthyl-1,1,8,8-tetracarboxylic dianhydride to obtain two novel iptycene-based poly[bis(benzimidazobenzisoquinolinones)]s (PBIBI–TPD and PBIBI–PPD) by a one-step, high-temperature solution polycondesation. Incorporation of iptycene groups especially the pentiptycene group in the polymer backbones improved their solubility and thermal stability. The resulting membranes exhibited good gas permeability owing to the high internal free volume elements introduced by the iptycene groups as well as high gas selectivity due to the restricted local segmental mobility arising from the interlocking of these groups in the polymer backbone. The membrane of PBIBI–PPD showed high CO₂ permeability (112 barrer) and moderately good CO₂/N₂ and CO₂/CH₄ selectivity (22 and 31) for mixed gas separation.

This paper was originally published in Polymer 55 (2014) Pages 102 - 109

To read about the winner and the nominated papers for the Best Chinese Paper 2014 award, please click here