Synthesis, characterization, thermal and electrochemical features of poly (phenoxy-imine)s containing pyridine and pyrimidine units

Abstract

Poly (4-hydroxybenzaldehyde) was prepared by via the oxidative polymerization process in an aqueous alkaline medium by H2O2 as an oxidant. Then, poly(phenoxy-imine)s were synthesized from the condensation reactions of poly(4-hydroxybenzaldehyde) (P-4HBA) with several amines including pyridine and pyrimidine groups. The structures and characterizations of compounds were made by virtue of FT-IR, NMR, UV–Vis spectroscopy, GPC, TG, DSC, CV, SEM and fluorescence (FL) analyses. The conductivities of poly (phenoxy-imine)s were determined with electrometer by four-point probe technique. The conductivity values of poly (phenoxy-imine)s were increased to be connect with doped factor of iodine. Moreover, the electrical conductivity of the poly (phenoxy-imine)s was also measured and defined which they had semi-conductive features. Fluorescence properties of poly (phenoxy-imine)s and P-4HBA were measured out in DMF solutions to define the optimum concentrations in order to acquire the maximal FL intensities. Average molecular weight of the polymers in number (Mn), and in weight (Mw), and polydispersity index (PDI) values of poly (phenoxy-imine)s and P-4HBA were found from GPC analysis. The Mn, Mw and PDI values of P-4HBA were found to be 9900 Da (Mn), 11,300 Da (Mw) and 1.14, respectively. The electrochemical energy gap (E’g) and optical band gap (Eg) values of poly (phenoxy-imine)s were determined from cyclic voltammetry (CV) and UV–Vis measurements, respectively.