Synthesis, characterization, thermal stability, conductivity, and band gap of a new aromatic polyether containing an azomethine as a side

摘要

In this study, the oxidative polycondensation reaction conditions of 4-[(4-methylphenyl)iminomethyl]phenol (4-MPfMP) were studied by using oxidants such as air 0,, H2O2, and NaOCl in an aqueous alkaline medium between 50 and 90 degrees C. The structures of the synthesized monomer and polymer were confirmed by FTIR, UV-vis, H-1-C-13-NMR, and elemental analysis. The characterization was made by TGA-DTA, size exclusion chromatography (SEC), and solubility tests. At the Optimum reaction conditions, the yield of poly-4[(4-methylphenyl)iminomethyl]phenol (P-4-MPIMP) was found to be 28% for air 02 oxidant, 42% for H2O2 oxidant, and 62% for NaOCl oxidant. According to the SEC analysis, the number-average molecular weight (M-n), weight-average molecular weight (M-w), and polydispersity index values of P-4-MPIMP were found to be 4400 g mol(-1), 5100 g mol(-1), and 1.159, using H2O2, and 4650 g mol-1, 5200 g mol(-1), and 1.118, using air 0,, and 5100 g mol-1, 5900 g mol-1, and 1.157, using NaOCl, respectively. According to TG analysis, the weight losses of 4-MPfMP and P-4-MPIMP were found to be 85.37% and 72.19% at 1000 degrees C, respectively. P-4-MPIMP showed higher stability against thermal decomposition. Also, electrical conductivity of the P-4-MPIMP was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital and the lowest unoccupied molecular orbital energy levels and electrochemical energy gaps (E-g(')) of 4-MPIMP and P-4-MPIMP were found to be -5.76, -5.19; -3.00, -3.24; 2.76 and 1.95 eV, respectively. According to UV-vis measurements, optical band gaps (E-g) of 4-MPIMP and P-4-MPIMP were found to be 3.34 and 2.82 eV, respectively. (c) 2007 Wiley Periodicals, Inc.