Artículos de revistas
Structure of chemically prepared poly-(para-phenylenediamine) investigated by spectroscopic techniques
Fecha
2009Registro en:
POLYMER, v.50, n.25, p.6043-6048, 2009
0032-3861
10.1016/j.polymer.2009.10.028
Autor
SESTREM, Ricardo H.
FERREIRA, Daniela C.
LANDERS, Richard
TEMPERINI, Marcia L. A.
NASCIMENTO, Gustavo M. do
Institución
Resumen
The structure of chemically prepared poly-p-phenylenediamine (PpPD) was investigated by Resonance Raman (RR), FTIR, UV-VIS-NIR, X-ray photoelectron (XPS), X-ray Absorption at Nitrogen K edge (N K XANES), and Electron paramagnetic Resonance (EPR) spectroscopies. XPS, EPR and N K XANES data reveal that polymeric structure is formed mainly by radical cations and dication nitrogens. It excludes the possibility that PpPD chains have azo or phenazinic nitrogens, as commonly is supposed in the literature. The RR spectrum of PpPD shows two characteristic bands at 1527 cm(-1) and 1590 cm(-1) that were assigned to nu C=N and nu C=C of dication units, respectively, similar to polyaniline in pernigraniline base form. The presence of radical cations was confirmed by Raman data owing to the presence of bands at 1325/1370 cm(-1), characteristic of nu C-N of polaronic segments. Thus, all results indicate that PpPD has a doped PANT-like structure, with semi-quinoid and quinoid rings, and has no phenazinic rings, as observed for poly-o-phenylenediamine. (C) 2009 Elsevier Ltd. All rights reserved.