Synthesis and characterization of new polyphenols derived from o-dianisidine: The effect of substituent on solubility, thermal stability, and electrical conductivity, optical and electrochemical properties


KAYA İ. , Yildirim M. , KAMACI M.

EUROPEAN POLYMER JOURNAL, cilt.45, ss.1586-1598, 2009 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 45 Konu: 5
  • Basım Tarihi: 2009
  • Doi Numarası: 10.1016/j.eurpolymj.2009.01.015
  • Dergi Adı: EUROPEAN POLYMER JOURNAL
  • Sayfa Sayıları: ss.1586-1598

Özet

In this study, we proposed to synthesize soluble polyphenol derivatives containing azomethine bond. For this reason, o-dianisidine was chosen to synthesize Schiff base monomers due to containing dimethoxy groups. Four phenolic Schiff bases were synthesized by condensation reaction of o-dianisidine with salicylaldehyde (2-HBADIAN), 4-hydroxybenzaldehyde (4-HBADIAN), vanillin (MHBADIAN) and 3-ethoxy-4-hydroxybenzaldehyde (EHBADIAN). These monomers were converted to their polyphenol derivatives via oxidative polycondensation reaction (OP). The structures of the obtained compounds were confirmed by FT-IR, UV-vis, H-1 NMR and C-13 NMR techniques. Progressing of OP was also followed by a time-controlled spectrum mode of a UV-vis spectrophotometer. The molecular weight distribution parameters of the synthesized polyphenols were determined by the size exclusion chromatography (SEC). The synthesized compounds were also characterized by solubility tests, TG-DTA and DSC. Cyclic voltammetry (CV) measurements were carried out and HOMO-LUMO energy levels and electrochemical band gaps (E'(g)) were calculated. Additionally, optical band gaps (E-g) were determined by using UV-vis spectra of the materials. Electrical conductivities of both doped and undoped states of the synthesized materials were measured by four-point probe technique using a Keithley 2400 electrometer showing that P-2-HBADIAN has approximately 130 times higher electrical conductivity than the others. Also, it was stressed that the synthesized polyphenols are semiconductors which have a potential for electronic and optoelectronic applications, with fairly low band gaps. (C) 2009 Elsevier Ltd. All rights reserved.