Thiourea-based hybrid sPEEK membranes using a Sol-Gel approach: Elaboration of stabilized hybrid sPEEK membranes
Résumé
Chemically stabilized hybrid membranes derived from sulfonated Poly (Ether Ether Ketone) membrane (sPEEK) have been developed for fuel cell applications. The synthesis is based on Sol Gel (SG) chemistry involving the in situ growth of a reactive SG phase containing antioxidant thiourea functions, namely N,N'-bis [3-(triethoxysilyl)propyl]thiourea (HTU) and N-phenyl,N'[3-(triethoxysilyl)propyl] thiourea (TTU) for SG uptake up to 20 wt%. Wellnanostructured sPEEK membranes with intact thiourea functional groups and a SG phase highly condensed (up to 85 %) and homogeneously dispersed are obtained. Despite the incorporation of the reactive silicate phase, the functional properties of the membrane electrolyte -namely thermal stability, water uptake, gas permeability, and ionic conductivity -are retained. Accelerated aging tests in H₂O₂ solution demonstrate the ability of the sol-gel (SG) phase to mitigate oxidative degradation, thereby significantly enhancing membrane durability.