Studies of the thermal behavior of Nafion® membranes treated with aluminum(III)

The effect of aluminum countercations on the thermal behavior of Nafion®-117 membrane was studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and accelerating rate calorimetry (ARC®). Aluminum countercations exchanged into a Nafion®-117 membrane were found to adversely affect the thermal properties of the membrane. The aluminum cations may give rise to a catalytic decomposition of the perfluoroalkylether (PFAE) side chains of the Nafion®. This result, together with some previously reported data, indicate that not just the size of the countercations, but the properties of the countercations themselves can also have a very strong effect on ionomer properties.