Anion-Conducting Polymer Electrolyte without Ether Linkages and with Ionic Groups Grafted on Long Side Chains: Poly(Alkylene Biphenyl Butyltrimethyl Ammonium) (ABBA)

Abstract

In this work we report the synthesis of the new ionomer poly(alkylene biphenyl butyltrimethyl ammonium) (ABBA) with a backbone devoid of alkaline-labile C-O-C bonds and with quaternary ammonium groups grafted on long side chains. The ionomer was achieved by metalation reaction with n-butyllithium of 2-bromobiphenyl, followed by the introduction of the long chain with 1,4-dibromobutane. The reaction steps were followed by 1H-NMR spectroscopy showing the characteristic signals of the Br-butyl chain and indicating the complete functionalization of the biphenyl moiety. The precursor was polycondensed with 1,1,1-trifluoroacetone and then quaternized using trimethylamine (TMA). After the acid catalyzed polycondensation, the stoichiometric ratio between the precursors was respected. The quaternization with TMA gave a final degree of amination of 0.83 in agreement with the thermogravimetric analysis and with the ion exchange capacity of 2.5 meq/g determined by acid–base titration. The new ionomer blended with poly(vinylalcohol) (PVA) or poly(vinylidene difluoride) (PVDF) was also characterized by water uptake (WU) and ionic conductivity measurements. The higher water uptake and ionic conductivity observed with the PVDF blend might be related to a better nanophase separation.

Separators and Membranes for Advanced Alkaline Water Electrolysis

“…Arene and ketone monomers functionalized with bromoalkyl and amine groups, respectively, ready for use in quaternization reactions have also been prepared in alternative routes in order to simplify synthesis or to study new AEM properties. For example, Narducci et al used lithiation chemistry to prepare a bromoalkylated biphenyl monomer 299 (Figure 16s), and Jannasch et al prepared bromoalkylated 2,2,2-trifluoroacetophenone (Figure 17f) in a one-step Friedel−Crafts reaction and used the monomer in a polyhydroxyalkylation with 4,4′biphenol to produce poly(xanthene)s (Figure 25a). 300 A xanthene AEM tethered with quinuclidinium cations had a conductivity above 100 mS cm −1 at 80 °C, and displayed high alkaline stability with no structural change or ionic loss detected by NMR analysis after 720 h in 2 M NaOH at 90 °C.…”

Impact of Anion Exchange Ionomers on the Electrocatalytic Performance for the Oxygen Reduction Reaction of B-N Co-doped Carbon Quantum Dots on Activated Carbon

“…Initially, the long side chain was inserted in 2,2′dibromobiphenyl (6.0 mmol) by a metalation route with n-BuLi (7.8 mmol) and 1,4-dibromobutane (15.6 mmol) in anhydrous THF at RT for 12 h. In the second step, the LC precursor (2.1 mequiv) in dichloromethane was condensed by acid-catalyzed Friedel−Crafts reaction with 1,1,1-trifluoroacetone (2.1 mmol) and trifluorosulfonic acid (22 mmol). In the final step, the polymer (1.5 mequiv) in NMP was quaternized with TMA (3.6 mmol) at 70 °C for about 72 h. The synthetic route was reported in detail in ref 35.…”