RADIATION GRAFTED MEMBRANES - SOME STRUCTURAL INVESTIGATIONS IN RELATION TO THEIR BEHAVIOR IN ION-EXCHANGE-MEMBRANE WATER ELECTROLYSIS CELLS

Structural investigations of three radiation grafted cation exchange membranes (Permion 4010, Permion 5010, CEC) have been performed by ESCA and EPMA (microprobe), and compared with published data of Nafion membranes. The two Permion membranes exhibit segregation of grafted and base polymer at the surface and within the volume, in contrast to Nafion and the CEC membrane. The membranes were tested in ion-exchange-membrane water electrolysis cells at 80-degrees-C for their short- and long-term operation behavior. Differences in cell voltage for short operation times are only due to different membrane resistivities and, therefore, a common iR-corrected cell voltage is measured. Long-term stability is related to polymer morphology: membranes with segregation degradate under the selected conditions, in contrast to membranes without segregation.