Thermal Degradation Kinetics of a Novel Pyrazole Based Copolymer [poly(1,3-diphenyl-1H-pyrazol-5-yl methacrylate-co-styrene)]

Abstract

In the present study, a new copolymer containing pyrazole substituted 1,3-diphenyl-1H-pyrazol-5-yl methacrylate (DPMA) and styrene (St) units, [poly(DPMA-co-St)], was synthesized. Thermal degradation kinetics of the copolymer system was investigated in detail with the thermogravimetric analysis (TGA) technique. An increase in the thermal stability of the copolymer from 252.02 °C to 274.89 °C was observed depending on the change in heating rate (5 °C/min – 20 °C/min). The thermal degradation activation energies of the copolymer were 149.37 kJ/mol and 140.99 kJ/mol, respectively, with the Kissinger and Flynn-Wall-Ozawa methods in the conversion range of 9% - 21%. The thermal degradation mechanism of the copolymer was investigated in the light of different kinetic methods such as Coats-Redfern, Tang, Madhusudanan, Van-Krevelen and Horowitz-Metzger. The results showed that the thermal decomposition mechanism of the copolymer proceeds through a one-dimensional diffusion-type deceleration mechanism, namely the D1 mechanism, at the optimum heating rate of 20 °C/min, especially according to the Coats-Redfern method.