Properties and Alkaline Stability of Composite Anion Conducting Ionomers Based on Poly(phenylene oxide) Grafted with DABCO and Mg/Al Lamellar Double Hydroxide

Abstract

We studied composite anion exchange membranes made from poly(2,6-dimethyl-1,4phenylene oxide) (PPO) with grafted 1,4-diazabicyclo[2.2.2]octane (DABCO) and Mg/Al lamellar double hydroxide particles as inorganic filler. The mechanical and conductivity properties were measured in fully humidified conditions. The activation energy for conductivity amounts to (0.20 ± 0.01) eV. The degradation of the anion exchange membrane in 2 M NaOH at 60 °C was investigated during 168 h following the ionic conductivity, water uptake and ion exchange capacity as function of the alkaline treatment time. The degradation is rapid within the first hours and then slows down. The degradation was also studied by thermogravimetric analysis and FTIR spectroscopy, showing the various decomposition phenomena of the composite.

Anion Exchange Membranes with 1D, 2D and 3D Fillers: A Review

“…Composite membranes with DABCO-PPO and 30 wt% MgAl-LDH were prepared in 2020 by Pasquini et al [49]. The high amount of the second phase was chosen in order to understand the effect of the inorganic filler on alkaline and hydrolytic degradation.…”

Current Challenges on the Alkaline Stability of Anion Exchange Membranes for Fuel Cells

“…Over the last decade, several polyarylene ether (PAE) polymers have been widely adopted as the backbone in AEMs because of their good mechanical properties, film-forming ability, and thermal stability. Many innovative AEMs have been developed based on polymer backbones such as polyether ether ketone, [73,74] polyphenylene oxide (PPO), [75,76] polybenzimidazole, [77,78] and polyethersulfone [79,80] (Figure 4a). Recent reports have revealed that not only cations but also polymer backbones can undergo nucleophilic attack by OH À , resulting in polymer degradation, especially when polar bonds such as ether and sulfone are present in the backbones.…”

Aliphatic Anion Exchange Ionomers with Long Spacers and No Ether Links by Ziegler–Natta Polymerization: Properties and Alkaline Stability

“…Various strategies have been explored to decrease the degradation [18] including a change of the polymer backbone [19,20], the introduction of long side chains, [21][22][23][24], and the delocalization of the positive charge [13,25]. Similarly, the use of composites with stable inorganic materials in alkaline environments such as hydrotalcites have shown an improvement in mechanical properties [26][27][28][29].…”