Synthesis, characterization, thermal degradation and electrochemical properties of oligo-4-m-tolylazomethinephenol


Kaya I. , BAYRAKLI Y.

CHINESE JOURNAL OF POLYMER SCIENCE, cilt.24, ss.647-656, 2006 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 24 Konu: 6
  • Basım Tarihi: 2006
  • Doi Numarası: 10.1142/s0256767906001758
  • Dergi Adı: CHINESE JOURNAL OF POLYMER SCIENCE
  • Sayfa Sayıları: ss.647-656

Özet

The oxidative polycondensation reaction conditions of 4-m-tolylazomethinephenol (4-TAMP) in the presence of air 02 and NaOCl as oxidants were studied in an aqueous alkaline medium between 50 and 90 degrees C. The structures of the obtained monomer and oligomer were confirmed by FT-IR, UV-Vis, H-1- and C-13-NMR and elemental analysis techniques. The physical characterization was made by TG-DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of oligo-4-m-tolylazomethinephenol (O-4-TAMP) was found to be 62.50% (for air 02 oxidant) and 90.0% (for NaOCl oxidant), respectively. According to the SEC analysis, the number-average molecular weight (M-n), weight-average molecular weight (M-w) and polydispersity index (PDI) values of O-4-TAMP were found to be 2310, 2610 g mol(-1) and 1.13, respectively, using air O-2, and 1390, 17 10 g mol(-1) and 1.23, using NaOCl, respectively. According to TG-DTA analyses, O-4-TAMP was more stable than 4-TAMP against thermal decomposition. The weight losses of 4-TAMP and O-4-TAMP were found to be 68% and 58% at 1000 degrees C. Electrical conductivity of the O-4-TAMP was measured, showing that the polymer is a typical semiconductor. Electrochemically, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and electrochemical energy gaps (E-g') for 4-TAMP are -5.96, -3.22 and 2.74 eV, respectively. The HOMO, LUMO and (E-g') for O-4-TAMP are -5.78, -3.44 and 2.34 eV, respectively. According to UV-Vis measurements, optical band gaps (E-g) of 4-TAMP and O-4-TAMP were found to be 3.45 and 3.10 eV, respectively.