TY - JOUR
T1 - Synthesis and Characterization of 4-Vinylimidazolium/Styrene-Cografted Anion-Conducting Electrolyte Membranes
AU - Hamada, Takashi
AU - Yoshimura, Kimio
AU - Takeuchi, Kota
AU - Watanabe, Shun
AU - Zhao, Yue
AU - Hiroki, Akihiro
AU - Hagiwara, Tokio
AU - Shishitani, Hideyuki
AU - Yamaguchi, Susumu
AU - Tanaka, Hirohisa
AU - Radulescu, Aurel
AU - Ohwada, Kenji
AU - Maekawa, Yasunari
N1 - Funding Information:
This work was partially supported by the Advanced Low Carbon Technology Research and Development Program (ALCA) from the Japan Science and Technology Agency (JST) and Grant‐in‐Aid for Scientific Research (A) from Japan Society for the Promotion of Science (JSPS) (KAKENHI Grant No. 18H03850). S.W. gratefully thanks The Sasakawa Scientific Research Grant in The Japan Science Society (JSS) (Grant No. 27‐332). The authors would like to thank Enago for the English language review.
Publisher Copyright:
© 2021 Wiley-VCH GmbH
PY - 2021/6
Y1 - 2021/6
N2 - The β-hydrogen-free imidazole monomer, 2-methyl-N-methyl-4(5)-vinylimidazole (2M4VIm), is synthesized to prepare anion exchange membranes (AEMs). The radiation-induced graft polymerization of 2M4VIm and styrene is performed in poly(ethylene-co-tetrafluoroethylene), followed by N-alkylation and ion exchange reactions to prepare 4-vinylimidazolium-containing AEM (2M4VIm/St-AEM). AEMs that have a 6/4 2M4VIm/St molar ratio and 1.7 mmol g−1 ion exchange capacity (IEC) result in 75 mS cm−1 conductivity and 60% water uptake at room temperature in water, demonstrating enhanced values compared to previously reported 2-methyl-N-vinylimidazolium-containing AEMs (2MNVIm/St-AEM) that have a similar comonomer ratio and IEC. The small-angle neutron scattering measurements of dry and swollen 2M4VIm/St-AEM reveal hydrophilic/hydrophobic two-phase separation, as observed for 2MNVIm/St-AEM with a similar Im/St composition. 2M4VIm/St-AEMs exhibit higher alkaline stability in 1 m KOH at 80 °C at an early stage owing to the suppression of imidazolium β-elimination but lower long-term stability than that of 2MNVIm/St-AEM due to the ring-opening reaction of the imidazolium group due to its outward orientation from the graft main chain.
AB - The β-hydrogen-free imidazole monomer, 2-methyl-N-methyl-4(5)-vinylimidazole (2M4VIm), is synthesized to prepare anion exchange membranes (AEMs). The radiation-induced graft polymerization of 2M4VIm and styrene is performed in poly(ethylene-co-tetrafluoroethylene), followed by N-alkylation and ion exchange reactions to prepare 4-vinylimidazolium-containing AEM (2M4VIm/St-AEM). AEMs that have a 6/4 2M4VIm/St molar ratio and 1.7 mmol g−1 ion exchange capacity (IEC) result in 75 mS cm−1 conductivity and 60% water uptake at room temperature in water, demonstrating enhanced values compared to previously reported 2-methyl-N-vinylimidazolium-containing AEMs (2MNVIm/St-AEM) that have a similar comonomer ratio and IEC. The small-angle neutron scattering measurements of dry and swollen 2M4VIm/St-AEM reveal hydrophilic/hydrophobic two-phase separation, as observed for 2MNVIm/St-AEM with a similar Im/St composition. 2M4VIm/St-AEMs exhibit higher alkaline stability in 1 m KOH at 80 °C at an early stage owing to the suppression of imidazolium β-elimination but lower long-term stability than that of 2MNVIm/St-AEM due to the ring-opening reaction of the imidazolium group due to its outward orientation from the graft main chain.
KW - alkaline durability
KW - anion-conducting electrolyte membranes
KW - imidazole
KW - poly(ethylene-co-tetrafluoroethylene)
KW - radiation-induced graft polymerization
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U2 - 10.1002/macp.202100028
DO - 10.1002/macp.202100028
M3 - Article
AN - SCOPUS:85105157962
SN - 1022-1352
VL - 222
JO - Macromolecular Chemistry and Physics
JF - Macromolecular Chemistry and Physics
IS - 11
M1 - 2100028
ER -