Thermoplastic interpenetrating polymer networks based on polybenzimidazole and poly (1, 2-dimethy-3-allylimidazolium) for anion exchange membranes. (10th December 2017)

• Record Type: Journal Article
• Authors: Lin, Jingjing; Yan, Xiaoming; He, Gaohong; Chen, Wanting; Zhen, Dongxing; Li, Tiantian; Ma, Lin; Wu, Xuemei
• Is Part Of: Electrochimica acta. Volume 257(2017)
• Page Start: 9
• Page End: 19
• Publication Date: 2017-12-10
• Subjects: Anion exchange membrane -- Polybenzimidazole -- Thermoplastic interpenetrating polymer networks -- Mechanical stability -- Ionic conductivity; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2017.09.126
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Thermoplastic interpenetrating polymer network AEM based on PBI has been developed. Physically crosslinking makes better compatibility and chain flexibility than sIPN. Good balance achieves between conductivity and swelling (96.7 mS cm −1, 4.4%, 80 °C). Abstract: A new series of thermoplastic interpenetrating polymer network (TIPN) anion exchange membranes (AEMs) based on poly [2, 2′- (p-oxydiphenylene) −5, 5′-bibenzimidazole] (OPBI) and poly(1, 2-dimethy-3-allylimidazolium) (PDAIm) (PBI/DAIm TIPN) has been developed. With 1, 2-dimethy-3-allylimidazolium (DAIm) polymerization in presence of OPBI polymer chains, two kinds of uncrosslinked polymer chains, i.e. PDAIm and OPBI interpenetrate with each other to form a physically crosslinking network. Small steric hindrance effect of the DAIm monomer and non-covalent crosslinking interpenetrating polymer chains contribute to better compatibility and chains flexibility in the TIPN compared with the blend and semi-interpenetrating networks, which are evidenced by SEM and SAXS, promote the aggregation of hydrophilic groups and induce connective ionic conductive channels. PBI/DAIm TIPN membranes achieve well-balanced performance between high hydroxide conductivity and dimensional stability because of the dynamically forced compatibility feature of TIPN. Especially, the PBI/DAIm TIPN-65/0.5 membrane exhibits high hydroxide conductivity (96.7 mS cm −1 ) and low swelling ratio (4.4%) at 80 °C. With low overall alkali uptake (2.89%) and IEC (0.63 mmol g −1 ) of functional groups, it exhibits excellent chemical stability in 1 M KOH at 60 °C for 96 h (94.0% retention) and high tensile strength (48.2 MPa) in hydrated state. These observations suggest TIPN structure provides a promising solution to the electrochemical-mechanical balance of AEMs.