Thermal decomposition of low-density polyethylene: kinetic study using TGA and DTG data

pyrolysis of low-density polyethylene (LDPE) waste is considered as a highly efficient and promising recycling method. The aim of this work is to investigate the pyrolysis kinetics using three model-free methods (Friedman, Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS)) and two model-fitting methods (Arrhenius and Coates-Redfern). Thermogravimetric (TGA) and differential thermogravimetric (DTG) thermograms at 5, 10, 20 and 40 K min−1 showed a linear curve, which implies the first-order reactions. The kinetic parameter values (E_A and A) of LDPE were calculated at different conversions by three model-free methods, and the average values of activation energies obtained were in good agreement and ranged from 190.23 to 191.89 kJ/mol. These kinetic parameters were additionally calculated at different heating rates using the Arrhenius and Coates-Redfern methods.