Thermal degradation investigations of newly synthesized terpolymeric polychelates

Abstract A novel terpolymer p-phenylenediamine-thiosemicarbazide-formaldehyde (PTSF) has been synthesized by polycondensation of p-phenylenediamine and thiosemicarbazide with formaldehyde in the presence of dimethylformamide as a catalyst at 130 °C with 1:1:2 mol proportion of reacting monomers. The terpolymer metal complexes were prepared with Ni2+, Cu2+ and Zn2+ metal ions using PTSF terpolymer as a ligand. The structure of newly synthesized terpolymer and its metal complexes have been elucidated and confirmed on the basis of elemental analysis and various spectral techniques, namely FT-IR, UV–visible and NMR (1H and 13C) spectroscopy. Averages of the molecular weight of the terpolymer were measured by gel permeation chromatography. Surface features of the terpolymer and its metal complexes were investigated by scanning electron microscopy. The thermal decomposition pattern and the kinetics of thermal decomposition of the terpolymer and its metal complexes were measured by thermogravimetric analysis. Kinetic and thermodynamic parameters such as activation energy (Ea), order of reaction (n), frequency factor (Z), entropy change (ΔS), free energy change (ΔF) and apparent entropy (S*) were calculated using Freeman-Carroll and Sharp-Wentworth methods. Thermogravimetric was used to analyze the order of thermal stabilities of the terpolymer ligand and its metal complexes.