New membranes based on high performance polymers for proton exchange membrane fuel cells PEMFC ; Nouvelles membranes à squelette haute performance pour les piles à combustible PEMFC

The current work is directed to production of a proton conducting membrane for a proton electrolyte membrane fuel cell (PEMFC) as a main goal. The originality and the challenge of the membrane elaboration lie in the multi-step procedure: starting with the synthesis of a simple unit – an ionic monomer, continuing with polymerization and overall estimation of the polymer performance at laboratory scale, and ending with production of the required material of industrial quantity and testing in real conditions. All the steps, except the last one, are explicitly studied. Firstly, much attention in the dissertation is paid to description of a protocol for production and purification of the ionic monomers. It is due to complexity of ionic interactions in a system ‘product-solvent' and due to the main requirement of high purity for a monomer that attentive synthesis and treatment of the monomers must be provided. In total three new monomers, bearing perfluorosulfonic acid chains, are reported. Then, a number of polymerization reactions with different commercial non-ionic monomers are proposed. Two main families of proton conducting ionomers are described: random poly(arylene ether)s (PAEs) and poly(arylene ether sulfone)s (PAESs), both random and block-copolymers. They are synthesized in series of different IEC in order to follow the impact of the ionic group to the properties of the material. Additionally, a new structure of the ionomer is proposed, where the block-copolymer contains a hydrophilic block, synthesized from two monomers, bearing perfluorosulfonic acid (PFSA) groups. It allows maximally approximating the superacid lateral groups along the polymer chain that, most probably, contributes to better organization and interaction between the ionic sites. For further characterization of the novel polymers, they are cast to membranes by casting-evaporation method from their solutions in dimethylacetamide (DMAc). The influence of production temperature is described briefly. The membranes of different series are ...