Synthesis, characterization, optical, and electrochemical properties of thermal stable novel poly(azomethine-ether)s

Abstract

In this study, the novel Schiff base monomers were synthesized by condensation reactions. Then, these monomers were converted to poly(azomethine-ether)s by oxidative polycondensation (OP) reactions in an aqueous alkaline medium. The structural characterizations of compounds were carried out by FT-IR, NMR, and size exclusion chromatography (SEC). According to the SEC analysis, the calculated number-average molecular weight (Mn), weight average molecular weight (Mw), and polydispersity index values of P-2 and P-4 were found to be 17,500 g mol−1, 24,400 g mol−1, and 1.39; and 18,700 g mol−1, 25,600 g mol−1, and 1.36, respectively. The HOMO-LUMO energy levels, electrochemical (), and optical (Eg) band gaps of polymers were calculated from cyclic voltammetry (CV) and UV–vis measurements, respectively. CV was used to determine the electrochemical oxidation–reduction characteristics of polymers. Thermal characterizations of compounds were made by using TG-DTA and DSC techniques. According to TG analysis, polymers with higher initial degradation temperatures (Ton) than those of their monomers indicate that the synthesized polyphenols have higher thermal stabilities than their monomer species.