Design, synthesis, and gas permeation properties of polyimides containing pendent imidazolium groups

Abstract

Film‐forming polymers containing ionic groups have attracted considerable attention as emerging materials for gas separation applications. The aim of this article was to synthesize new film‐forming polyimides containing imidazolium groups (PI‐IMs) and establish their structure–performance relationship. In this context, a new aromatic diamine, namely, N1‐(4‐aminophenyl)‐N1‐(4‐(2‐phenyl‐1H‐imidazol‐1‐yl)phenyl)benzene‐1,4‐diamine (ImTPADA), was synthesized and polycondensed with three aromatic dianhydrides, namely, 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride, 4,4‐(4,4‐isopropylidenediphenoxy) bis(phthalic anhydride), and 4,4′‐oxydiphthalic anhydride to form the corresponding polyimides containing pendent 2‐phenylimidazole groups (PI‐IEs). Next, PI‐IMs were prepared by N‐quaternization of pendent 2‐phenylimidazole groups present in PI‐6FDA using methyl iodide followed by anion exchange with bis(trifluoromethane)sulfonimide lithium salt (LiTf2N). PI‐IEs and PI‐IMs exhibited reasonably high molecular weights, amorphous nature, good solubility, and could be cast into self‐standing films from their DMAc solutions. Thermogravimetric analysis showed that 10% weight loss temperature of PI‐IEs and PI‐IMs were in the range 545–475 °C and 303–306 °C, respectively. Gas permeability analysis of films of PI‐IEs and PI‐IMs was investigated by variable‐volume method and it was observed that incorporation of ionic groups into PI‐6FDA resulted in increased permeability while maintaining selectivity. In particular, polymer bearing Tf2N− anion exhibited high CO2 permeability (33.3 Barr) and high selectivity for CO2/CH4 (41.1) and CO2/N2 (35.4). © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1721–1729

Highly soluble fluorinated polyimides with promising gas transport performance and optical transparency

“…65 Although 6FDA-BASA show relatively large gas permeability, the selectivity is reduced. But it can be observed that compared with PI-6FDA 66 with similar gas permeability reported at present, the gas selectivity of 6FDA-BASA has no great loss. The O 2 permeability and O 2 /N 2 selectivity of 6FDA-BASA were closest to the 1991 upper bound.…”

Polymerization-tailored polyimides as cathodes for lithium-ion batteries

“…For the sPI prepared via solvothermal polymerization, the PXRD pattern shows a broad peak indicating its amorphous feature. 19 While cPI prepared via conventional polymerization displays a weak peak at 5.691 corresponding to the (200) plane, suggesting a low crystallinity with poor long-range periodicity. 20 It is noteworthy to mention that PI-COF reveals the first and most intensive peak at 2.71 attributed to (100) along with minor peaks at 5.61 and 7.31 assigned to the (200) and (210) planes, respectively, demonstrating the formation of ordered domains with high crystallinity (as illustrated in Fig.…”

New fluorinated polyimides based on 1,2-bis(4-aminophenyl)-4,5-bis(4-trifluoromethylphenyl)-1H-imidazole

“…29,30 In previous work, some aromatic PIs and poly(ether imide)s containing di-and triarylimidazolyl units into the polymer backbone or as bulky pendant groups have been reported. [31][32][33][34][35][36][37][38][39] In this paper, with an aim to develop high performance and processable PIs, a new kind of unsymmetrical diamine containing tetraarylimidazolyl and trifluoromethyl groups, 1,2diphenyl-4,5-bis(4-trifluoromethylphenyl)-1H-imidazole, has been synthesized successfully. Meanwhile, a new series of fluorinated imidazolyl-containing PIs were synthesized derived from the resulting diamine monomer.…”