ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Chromaticity of poly( o -toluidine) matrix enhanced by anion-exchange mechanism

S. M. Ahmed

Chemistry Department, Faculty of Science, Assiut University, 71516 Assiut, Egypt

E-mail: sm_ahmed@yahoo.com

Received: 6 February 2007  Revised: 20 March 2007  Accepted: 23 March 2007

Abstract: The incorporation of 9,10-anthraquinone-1,5-disulfonate (AQS₂) into the protonated form of poly(o-toluidine) (POT), produced by oxidative polymerization of the cationic form of the monomer or by doping the basic form (POT-EB) by anion-exchange has been studied by FTIR and UV-VIS spectroscopy and mass spectrometry. The presence of sulfur and the absence of chlorine proven by elemental analysis of the polymer product confirmed the substitution of the chloride anion with AQS₂ in the matrix. Molecular mechanics (MM+) calculations suggest that the optimal geometric structure (OMG) of AQS₂-doped POT is at least three (3.92) times more stable than that of the parent chloride-doped POT (HCl-doped POT). The increase of the absorbance at about 840 nm associated with the increasing concentration of AQS₂ revealed the insertion of AQS₂ into the POT chain. This observation could be explained by the diffusion of AQS₂ in the polymer chain. Kinetic parameters of the oxidative polymerization of the cationic form of o-toluidine (o-T-HClO₄) in the presence of different amounts of AQS₂ were deduced on the basis of absorbance variations. The results of computer-oriented kinetic analysis indicate that the rate-controlling step of the o-T polymerization is governed by the Ginstling-Bronstein equation representing the three-dimensional diffusion (D4). Activation parameters of the oxidative polymerization of protonated o-T in the presence of varying amount of AQS₂ were computed and discussed.

Keywords: chromaticity - poly(o-toluidine) - 9,10-anthraquinone-1,5-disulfonate - activation parameters - molecular mechanics (MM+) calculations

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-007-0063-y

Chemical Papers 61 (6) 464–471 (2007)