Polymeric proton exchange media with ionic bonds in the main chain of the polymer

Abstract

This paper proposes a method of obtaining the first representative of a polymeric proton-conducting medium with protic ionic groups in the main chain of a polymer by the mutual neutralization of linear telechelic oligomers with end groups of the basic and acidic nature. Oligoethylene oxide containing 1-(3-aminopropyl) imidazole fragments with two types of basic centers (aliphatic secondary amine groups and imidazole fragments) at the ends of the chain was used as the oligomer with basic properties. Sulfonic acid-terminated oligoethylene oxide was used as the acid oligomer. Protonation of aliphatic secondary amino groups in the composition of the oligomer of the basic type with the formation of an ion-elongated polymer chain is more probable at the equimolar ratio of the starting compounds according to the analysis of ΔKa values. It is shown that the synthesized polymer contains two types of crystalline formations with melting points of 37.6 °C and 46.2 °C and turns into a liquid state, when heated to higher temperature values. The proton conductivity of the polymer under anhydrous conditions is close to the conductivity of the initial sulfonic acid-terminated oligomer in the temperature inter val of 40-100 °C and reaches 2.3 · 10–4 S/cm at 100 °C, despite a much lower content of proton charge carriers.