Polymerization of isatin towards polymers for anion exchange membranes and gas separation applications

Abstract: In a world where the problem of energy resources, pollution and all aspects related to these issues becomes more and more dominant, a greater commitment is needed in the search for solutions. The goal of this project is to make a contribution to the research and development of new materials to reduce the environmental impact in some fields. First of all, we tried to synthesize and prepare an isatin-based membrane which has the potential for use in separating industrial gases. Furthermore, ion exchange membranes, specifically hydroxide exchange membranes (HEMs) derived from the same material were developed for fuel cells (HEMFC) applications. These materials are essential for energy conversion and storage. The most difficult challenge is to guarantee their thermal stability and stability in corrosive environments such as alkali without losing efficiency. In recent years the polyhydroxyalkylation catalysed with superacids, e.g. TFSA, has become increasingly studied. This reaction is exploited for the synthesis of the compounds of this thesis. After a preliminary optimization of the reaction conditions it was concluded that, due to the rigidity and excessive reactivity of the monomers, it was not possible to obtain the isatin-based membrane to evaluate the gas separation properties. The synthesis of precursor materials for HEMs was successful. Instead of isatin, 1-(4-bromobutyl)indoline-2,3-dione (BID) was used as a substitute. A characterization of the polymers was carried out using NMR, TGA and DSC analyses, and subsequently the membranes were functionalized with different ammonium-based cations. Unfortunately, this last step was not successful due to the appearance of side reactions. Future studies on the mechanism and kinetics of the reaction may solve this obstacle.