Co-pyrolysis of low-density polyethylene and polystyrene: thermodynamic feasibility, kinetics, and artificial neural network modelling

Abstract

In this study, the performance and synergy of the co-pyrolysis of low-density polyethylene (LDPE) and polystyrene (PS) were investigated using thermogravimetric analysis (TGA) and artificial neural network (ANN) modelling. The plastic waste samples were obtained from the vicinity of the Obafemi Awolowo University, Ile-Ife, Nigeria and subjected to proximate/ultimate analysis, scanning electron microscopy, and TGA. The results of the proximate analysis revealed a volatile matter of 76.90%, a low moisture content of 9.67%, a low ash content of 0.91%, and low contents of nitrogen (2.73%) and sulphur (0.83%) alongside a higher heating value of 22.92 MJ kg −1 , all demonstrating the suitability of the LDPE-PS blend as a biofuel feedstock. The TGA indicated three weight loss regions, with the second temperature region (123-518°C) accounting for the predominant weight loss of the LDPE-PS blend. The Free Gibbs energy change suggests a large bioenergy potential for the LDPE-PS blend. The ANN demonstrated a high predictive accuracy (R 2 ≥ 0.999), showing the agreement between the experimental and predicted weight loss data. These findings accentuate the fuel-generative potential of the LDPE-PS blend whilst underscoring the reliability of ANN in predictive modelling of polymer blend pyrolysis behaviour.