H[sup +] and Na[sup +] Ion Transport Properties of Sulfonated Poly(2,6-dimethyl-1,4-phenyleneoxide) Membranes

Abstract

Diffusion coefficients of H ϩ and Na ϩ ions in sulfonated poly͑2,6-dimethyl-1,4-phenylene oxide͒ ͑PPO͒ intermolecularly crosslinked with poly͑2-butylaniline͒ ͑PBA͒ or poly-͓2,2Ј-(m-phenylene)-5,5Ј-bibenzimidazole͔ ͑PBI͒ were evaluated by conductivity and H ϩ /Na ϩ ion exchange measurements. Ion exchange capacity and transport properties of the PPO membranes with a degree of sulfonation higher than 30% are comparable to those of Nafion. The observed deterioration of ion exchange capacity and ion transport with increasing content of the cross-linking agent is related to the partial occupation of the fixed sulfo groups by the tertiary nitrogen groups present in PBA and PBI.

Covalent‐Ionically Cross‐linked Poly(Etheretherketone)‐Basic Polysulfone Blend Ionomer Membranes

“…It has been established at other ionically crosslinked blend membrane systems such as the blend membranes of sulfonated poly(etherketones) and the extraordinary stable polymeric base PBI, that ionic cross-linking obviously enhances the thermal stabilities of sulfonated ionomer membranes [9]. These findings have been confirmed by other groups, e.g., for ionically cross-linked blend membrane systems of sulfonated polyphosphazenes and PBI [14], for blends of sulfonated PPO and PBI [12,13], for meta-sulfonesulfonated PPSU/PBI blend membranes [32], and for ortho-ether-sulfonated PSU/ PBI blend membranes [33].…”

Sulfonated hydrocarbon membranes for medium-temperature and low-humidity proton exchange membrane fuel cells (PEMFCs)

“…Ionic crosslinking. Ionic crosslinking is effective for reinforcing the mechanical strength of PEM materials [149][150][151][152]. Crosslinking is mainly achieved by blending a sulfonated copolymer, particularly in the form of a salt (e.g., -SO 3 − Na + ), with a basic polymer (e.g., polybenzimidazole (PBI)).…”

Blend Membranes Consisting of Sulfonated Poly(ether ether ketone) and Polysulfone Bearing 4-Nitrobenzimidazole for Direct Methanol Fuel Cells

“…Also, acid-base blends containing ionic cross-links, such as Nafion/PBI, SPEEK/PBI, and SPPO/PBI ͓PBI and SPPO refer, respectively, to poly͑benzimidazole͒ and sulfonated poly͑2,6-dimethyl-1,4-phenylene oxide͔͒, have been found to exhibit lower methanol crossover in DMFCs. [23][24][25][26] Unfortunately, they usually lead to a sacrifice in fuel cell performance, and microphase separation is easy to occur in such blends due to the incompatibility between the acidic and basic ͑polybenzimidazole͒ polymer structures. 27,28 Recently, we reported that polysulfone bearing benzimidazole ͑PSf-BIm͒ or amino-benzimidazole ͑PSf-ABIm͒ side groups could promote proton conduction in SPEEK under anhydrous conditions through acid-base interaction between the sulfonic acid groups of the SPEEK and the nitrogen atoms of the benzimidazole groups tethered to similar aromatic backbones.…”