Novel homo- and co-poly(p-phenyene ether sulfone benzimidazole/sulfide sulfone benzimidazole)s: synthesis and properties

Li, Zhimin; Zhang, Gang; Li, Yan; Yang, Jie

doi:10.1007/s10965-015-0724-4

Cited by 3 publications

(1 citation statement)

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“…However, IM-PAES-sIM does not show an observable glass transition within the tested temperature below 180 °C. However, as seen from the reported literature, − some polymers having benzimidazole structures do not undergo glass transitions at temperatures lower than 300 °C, indicating that the chains of polymers containing benzimidazole structures are more difficult to move than those of polymers containing alkyl chain structures. From the TGA and DSC discussions, it seems that IM-PAES-sIM AEM with the benzimidazole structure has a more rigid polymer backbone relative to the 12A-PAES-sIM AEM with alkyl chain segments. , …”

Section: Results and Discussionmentioning

confidence: 67%

Subnanometer Ion Channel Anion Exchange Membranes Having a Rigid Benzimidazole Structure for Selective Anion Separation

et al. 2022

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Ion-conductive polymers having a well-defined phase-separated structure show the potential application of separating mono- and bivalent ion separation. In this work, three side-chain-type poly(arylene ether sulfone)-based anion exchange membranes (AEMs) have been fabricated to investigate the effect of the stiffness of the polymer backbone within AEMs on the Cl–/NO3 – and Cl–/SO4 2– separation performance. Our investigations via small-angle X-ray scattering (SAXS), positron annihilation, and differential scanning calorimetry (DSC) demonstrate that the as-prepared AEM with a rigid benzimidazole structure in the backbone bears subnanometer ion channels resulting from the arrangement of the rigid polymer backbone. In particular, SAXS results demonstrate that the rigid benzimidazole-containing AEM in the wet state has an ion cluster size of 0.548 nm, which is smaller than that of an AEM with alkyl segments in the backbone (0.760 nm). Thus, in the electrodialysis (ED) process, the former exhibits a superior capacity of separating Cl–/SO4 2– ions relative to latter. Nevertheless, the benzimidazole-containing AEM shows an inability to separate the Cl–/NO3 – ions, which is possibly due to the similar ion size of the two. The higher rotational energy barrier (4.3 × 10–3 Hartree) of benzimidazole units and the smaller polymer matrix free-volume (0.636%) in the AEM significantly contribute to the construction of smaller ion channels. As a result, it is believed that the rigid benzimidazole structure of this kind is a benefit to the construction of stable subnanometer ion channels in the AEM that can selectively separate ions with different sizes.

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