Co-pyrolysis of poly (lactic acid) and sesame stalk: Synergistic effect, kinetic and thermodynamic studies

For the study of the biomass effect on pyrolysis of plastic wastes, co-pyrolysis features and kinetics of poly (lactic acid) (PLA)/sesame straw hybrids have been investigated for the first time by experimental evaluation and theoretical analysis. Our results show that the onset pyrolysis temperatures of PLA have decreased considerably after blending with sesame straw and there is a considerable synergistic effect between two feedstocks. Based on nonisothermal results, kinetic analysis has been isoconversionally made by using integral and differential methods and their performances in obtaining activation energy are fully compared. The calculations show that the activation energies are 115.8∼150.1, 150.7∼210.1 and 132.2∼178.5 kJ/mol for the PLA mixtures with the sesame straw content 10, 20 and 30 mass%, respectively. The pre-exponential factor has been calculated model-freely with the use of the compensation effect while the reaction mechanism function has been appropriately determined by following the Master plots method. Additionally, thermodynamic analysis for the entire pyrolysis is also done in terms of enthalpy, entropy and Gibbs free energy changes. Overall, the results acquired from this work may open up new avenues for thermally disposing waste plastics and advancing sustainable energy generation.