Thermal kinetic parameters and evolved gas analysis (TG–FTIR–MS) for thiourea–formaldehyde based polymer metal complexes

Abstract

Two polymer metal complexes with a general formula of TUF–M(II) (M=Co, Cu) were synthesized by the reaction of a thiourea–formaldehyde resin (TUF) and transition metal ions. The thermal degradation of TUF–M(II) was investigated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA) during pyrolysis and combustion. The kinetic parameters for the thermal degradation were evaluated using the Coats–Redfern and Friedman equations. An evolved gas analysis (EAG) during the thermal decomposition of TUF–M(II) was performed for the pyrolysis and combustion up to 800°C using both online coupled TG–FTIR and simultaneous TG–MS. The emissions of CS2, NH3, SO2, COS, HCN, H2NCN and HNCS were identified during the thermal degradation of TUF–M(II). The total mass loss resulting from the pyrolysis of TUF–Cu(II) at 775°C was 73.26%, while 44.02% of the original mass was lost at 225–325°C. The activation energy for the second stage of degradation of the combustion (189.2KJmol−1, 184.5KJmol−1) was higher than that of the pyrolysis (179.8KJmol−1, 175.1KJmol−1) at a similar stage for both complexes using the Coats–Redfern method.