Azomethine-based phenol polymer: Synthesis, characterization and thermal study

Abstract

Azomethine-based phenol polymer, poly-2-{[(6-aminopyridin-2-yl)imino]methyl}-phenol (PAPIMP), was synthesized through the combination of condensation reaction and oxidative polymerization. Polymer isolated from aqueous solution was characterized by UV–vis, FT-IR, NMR and TG, SEC analysis. According to the SEC chromatograms, the number-average molecular weight (Mn), weight-average molecular weight (Mw) and polydispersity index (PDI) values of PAPIMP were determined to be 33,550, 78,900gmol−1 and 2.352, respectively. Also, optical band gaps (Eg) of APIMP and PAPIMP calculated from cyclic voltammetry (CV) measurements. Also, electrical conductivities of each component measured with four-point probe technique. TG analysis showed that PAPIMP was stable up to 300°C. The thermal decomposition kinetics of PAPIMP was investigated by means of thermogravimetric analysis in dynamic nitrogen atmosphere at four different heating rates: 5, 10, 15 and 20°Cmin−1. The apparent activation energies for thermal decomposition of PAPIMP were obtained by Tang, Flynn–Wall–Ozawa (FWO), Kissenger–Akahira–Sunose (KAS) and Coats–Redfern methods (CR) were 96.97, 105.33, 97.28 and 88.60kJmol−1, respectively; the mechanism function and pre-exponential factor were determined by master plots method. The most likely decomposition process was a Dn Deceleration type in terms of the Coats–Redfern and master plots results.