Synthesis by chemical oxidation and characterization of poly(o-ethoxyaniline) (POEA)

POEA is a new type of conductive polymer. To our knowledge, Chinese reseachers have not yet carried out a deep research on this issue. In this paper, we synthesized POEA by chemical oxidation, using hydrochloric acid as dopant. The crystalline phase, microstructure, surface appearance, molecular weight and its distribution, oxidation-reduction degree, conductivity and thermostability of POEA were characterized. X-Ray diffraction (XRD) spectrogram suggested that POEA was amorphous. Fourier transform infrared (FTIR) spectroscopy showed that there were C-O-C ether bonds in POEA, which polyaniline does not have. Solid state nuclear magnetic resonance ( ¹³C-NMR) spectrogram indicated that the spectrogram of product was approximately identical with the spectrogram of theoretical structure. Scanning electron microscopy (SEM) photo revealed that POEA was sheeted. Gel permeation chromatography (GPC) results demonstrated that molecular weight distribution was 10 ⁴~10 ⁶. Ultraviolet-Visible (UV-Vis) spectroscopy results illustrated that oxidation index 1-x was about 0.5. The conductivity was about 2.7×10 ^-4S/cm as measured by four-probe method. The dielectric losses were higher in lower frequency range (2~10 GHz) as measured by vector network analyzer (VNA). Differential scanning calorimetry (DSC) results made clear that the cross-linking heterogeneous reaction might happen at about 200°C. Thermogravimetric analysis (TGA) results indicated that the thermal decomposition temperature could achieve more than 300°C.