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

We studied composite anion exchange membranes made from poly(2,6-dimethyl-1,4-phenylene 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 degrees 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.