Aliphatic Anion Exchange Ionomers with Long Spacers and No Ether Links by Ziegler–Natta Polymerization: Properties and Alkaline Stability
Raul Andres Becerra-Arciniegas,
Riccardo Narducci,
Gianfranco Ercolani,
Luca Pasquini,
Philippe Knauth,
Maria Luisa Di Vona
Affiliations
Raul Andres Becerra-Arciniegas
Department of Industrial Engineering and International Laboratory “Ionomer Materials for Energy”, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Roma, Italy
Riccardo Narducci
Department of Industrial Engineering and International Laboratory “Ionomer Materials for Energy”, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Roma, Italy
Gianfranco Ercolani
Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133 Roma, Italy
Luca Pasquini
Aix-Marseille Univ, CNRS, MADIREL (UMR 7246) and International Laboratory “Ionomer Materials for Energy”, Campus St Jérôme, 13013 Marseille, France
Philippe Knauth
Aix-Marseille Univ, CNRS, MADIREL (UMR 7246) and International Laboratory “Ionomer Materials for Energy”, Campus St Jérôme, 13013 Marseille, France
Maria Luisa Di Vona
Department of Industrial Engineering and International Laboratory “Ionomer Materials for Energy”, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Roma, Italy
In this work we report the synthesis of poly(vinylbenzylchloride-co-hexene) copolymer grafted with N,N-dimethylhexylammonium groups to study the effect of an aliphatic backbone without ether linkage on the ionomer properties. The copolymerization was achieved by the Ziegler–Natta method, employing the complex ZrCl4 (THF)2 as a catalyst. A certain degree of crosslinking with N,N,N′,N′-tetramethylethylenediamine (TEMED) was introduced with the aim of avoiding excessive swelling in water. The resulting anion exchange polymers were characterized by 1H-NMR, FTIR, TGA, and ion exchange capacity (IEC) measurements. The ionomers showed good alkaline stability; after 72 h of treatment in 2 M KOH at 80 °C the remaining IEC of 76% confirms that ionomers without ether bonds are less sensitive to a SN2 attack and suggests the possibility of their use as a binder in a fuel cell electrode formulation. The ionomers were also blended with polyvinyl alcohol (PVA) and crosslinked with glutaraldehyde. The water uptake of the blend membranes was around 110% at 25 °C. The ionic conductivity at 25 °C in the OH− form was 29.5 mS/cm.
