Preparation and properties of anion exchange membranes having pyridinium or pyridinium derivatives as anion exchange groups

Abstract

Anion exchange membranes with pyridinum groups and various pyridinium derivative groups were prepared from a copolymer membrane composed of chloromethylstyrene and divinylbenzene, and pyridine and pyridine derivatives. The anion exchange membranes obtained showed excellent electrochemical properties in electrodialysis. The transport numbers of sulfate ions, bromide ions, nitrate ions, and fluoride ions relative to chloride ions were evaluated in connection with the species of a substituent and the position of the substituent in the pyridinium groups. In general, when a hydrophilic substituent (methanol groups) existed at the 2‐position of the pyridinium groups, nitrate ions and bromide ions, which are less hydrated, permeated through the membranes with difficulty, and sulfate ions permeated selectively through the membranes. On the other hand, when hydrophobic groups, for example, ethyl groups, existed at the 2‐position of the pyridinium groups, bromide ions and nitrate ionspermeated selectively through the membranes and fluoride ions had difficulty permeating through the membranes. The carbon number of the alkyl chain of 4‐alkyl pyridinium groups also affected permeation of nitrate ions and bromide ions due to the change in hydrophilicity of the membranes. Though the hydration of the anions and the species of the substituent at the 2‐position of the pyridinium groups were related to selective permeation of the anion through the membranes, permeation of sulfate ions was not as sensitive to the hydrophilicity of the membranes. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 49–58, 1998

Anion exchange membranes for alkaline fuel cells: A review

“…Neagu et al [65] addressed the stability of pyridinium and Sata et al [82][83][84][85] published several papers on poly(vinyl pyridinium) membranes. Even though these membranes show excellent electrochemical properties in electrodialysis, the pyridinium group is prone to degradation in alkaline media.…”

“…Sata and colleagues [82][83][84][85] have carried out a lot of work on poly(vinyl pyridinium) membranes. However, because of the instability of pyridinium in alkaline conditions [73], corresponding membranes cannot find any applications in AFCs and are not described in this review.…”

Ion exchange membranes: State of their development and perspective

“…Grafting copolymerization of pyridine and its derivative onto polymer films and then quaternization with alkyl halide as mentioned above provide examples of such membranes. The chloromethyl methyl ether can also be avoided by directly grafting vinylbenzylchloride onto polymer films or by copolymerizing with other monomers, such as divinylbenzene (DVB) to form copolymer films that can be converted to anion exchange membrane by simple amination reaction [85][86][87]. Copolymerization of epoxy acrylate monomers, such as glycidyl acrylate or glycidyl ethacrylate with other monomers, such as divinylbenzene subsequent amination with triethyl amine can serve as alternative route to prepare anion exchange membranes [88].…”

Fundamental studies of a new series of anion exchange membranes: Membranes prepared from bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) and pyridine

“…As an example of how this can be achieved, anions with different ion hydration energies can be effectively separated by changing the hydrophobicity of the membranes [15]. Sata et al [16][17][18][19] reported the reaction of a copolymer synthesized from chloromethylstyrene and divinylbenzene with different amines, such as trimethylamine (TMA) and 4-vinylpyridine. Since the hydrophilic-lipophilic balance (HLB value) of TMA is higher than that of pyridine (14.98 and 14.03 for TMA and 4-vinylpyridine, respectively) [19], the hydrophilicity of the obtained membranes was different, which led to the membranes demonstrating different permselectivity for anions with different hydration energies; however, the preparation process of these copolymer membranes is relatively complicated, i.e.…”