Use of a new crosslinking method to obtain semi-IPN membranes with phosphonic acid groups for a PEMFC application

The synthesis of a new semi-IPN membrane was performed from a commercial fluorinated copolymer and a fluorophosphonated copolymer with pendant phosphonic acid groups. The crosslinking of the fluorophosphonated copolymer was done from the presence of sulfonated groups by a simple heat treatment. Several membranes are cast with a crosslinking rate range from 5 to 20% and a molar percent of phosphonic acid range from 38 to 12%. These kinds of PEMFCs show proton conductivity in a reach magnitude of 10 −3 S cm −1 in humidified conditions. All the membranes possess a high thermal stability. The mechanical behaviour of all membranes was determined by DMA as a function of the temperature and the relative humidity.