Synthesis, characterization, thermal analysis, and band gap of oligo‐2‐methoxy‐6‐[(4‐methylphenyl)imino]methylphenol

Abstract

AbstractThe oxidative polycondensation reaction conditions of 2‐methoxy‐6‐[(4‐methylphenyl)imino]methylphenol (2M‐4‐MPIMP) by using oxidants such as air O2, H2O2 and NaOCl were studied in an aqueous alkaline medium between 30 and 90°C. The structures of synthesized monomer and oligomer were confirmed by FTIR, UV–vis, 1H NMR, 13CNMR, and elemental analysis. The characterization was made by TG–DTA, size exclusion chromatography (SEC), and solubility tests. At the optimum reaction conditions, the yield of oligo (O)‐2M‐4‐MPIMP was 68% for air O2 oxidant, 68% for H2O2 oxidant, and 82% for NaOCl oxidant. According to the SEC analysis, the number– average molecular weight (Mn), weight–average molecular weight (Mw), and polydispersity index (PDI) values of O‐2M‐4‐MPIMP were found to be 695, 1000 g mol−1 and 1.439, using air O2, and 670, 795 g mol−1 and 1.187, using NaOCl, and 645, 790 g mol−1 and 1.225, using H2O2, respectively. TG–DTA analyses were shown to be stable of O‐2M‐4‐MPIMP against thermal decomposition. The weight losses of 2M‐4‐MPIMP and O‐2M‐4‐MPIMP were found to be 98.46% and 89.54% at 1000°C, respectively. Also, electrical conductivity of the O‐2M‐4‐MPIMP was measured, showing that the polymer is typical semiconductor. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of monomer and oligomer were determined from the onset potentials for n‐doping and p‐doping, respectively. Optical energy gaps (Eg) of 2M‐4‐MPIMP and O‐2M‐4‐MPIMP were calculated from UV–vis measurements. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007