A study of the chemical and the enzyme-catalyzed oxidative polymerization of aromatic diamine bearing chlor substituents, pursuant to structural, thermal and photophysical properties
Feyza Kolcua,b, Ismet Kayaa
Polymer Synthesis and Analysis Laboratory, Department of Chemistry, Çanakkale Onsekiz Mart University, 17020 Çanakkale, Turkey.
2,5-Dichloro-p-phenylenediamine (ClPDA) is a member of aromatic diamines. This descriptive study sought the oxidative polymerization of ClPDA with hydrogen peroxide using the enzyme-catalyzed and the chemical oxidative ways for the syntheses of P-ClPDA-E and P-ClPDA-O, respectively. Neutral ClPDA was easily oxidized to the polymers composed of ortho-coupled constitutional moieties with lower optical and electrochemical band gaps than those of ClPDA using two polymerization routes. The elucidation of molecular structures obtained from the enzyme-catalyzed and the chemical oxidative polymerization of ClPDA were carried out by the FT-IR, UV–Vis, 1H NMR and 13C NMR techniques, concluded with the ladder-type and the perrnigraniline-type polymer formation as a result of two different polymerization processes. Solvent effects in selected polar solvents on the optical properties of P-ClPDA-E and P-ClPDA-O were also analyzed. Thermal and electrochemical properties of the products were fulfilled using TG-DTA-DSC and cyclic voltammetry (CV) techniques, respectively. The number of average molecular weight of P-ClPDA-E was found to be higher than that of P-ClPDA-O. The degradation of ladder-type structure of P-ClPDA-E with higher Mw value started at higher temperatures compared to P-ClPDA-O, which was composed of benzenoid and quinoid units. In response to the excitation of UV light, only P-ClPDA-E radiated blue light with high intensity and a quantum yield of 23% in DMF depending on photoluminescence measurement. Scanning Electron Microscopy (SEM) views set a precedent for the agglomerates of particles. The enzyme-catalyzed oxidation of ClPDA resulted in the formation of nanospheres of P-ClPDA-E. In course of a change in the polymerization method, the morphology of the chemical oxidative polymerized ClPDA (P-ClPDA-O) was seen spongy with some pores.
Keywords : Methane oxidation, Selenate reduction, Membrane biofilm batch reactor, Mixed consortium, Wastewater treatment.