Kinetic study of pyrolysis of waste polystyrene and polyethylene mixture using novel non‐isothermal method

Abstract

AbstractA tremendous increase in municipal plastic waste is observed due to high consumption of polymers. With the passage of time the available landfills for discarding of waste plastics decrease whereas, appropriate recycling methods for waste plastics gaining more and more importance. In the present work thermal decomposition of polystyrene (PS) and polyethylene (PE) waste mixture was carried out at different heating rates (5, 10, 15 and 20 °C/min) in a thermogravimetric analyzer (TGA). Thermogravimetric data obtained was further interpreted using new developed non‐isothermal integral method and compared it with several kinetic models i. e., Coats Redfern (CR), Ozawa Flynn Wall (OFW), Kissinger‐Akahira‐Sunose (KAS), Achar and Criado‐Dollimore (CD). The activation energy (Ea) calculated using CR, OFW, KAS, Achar and CD models were found to be in the range of 92.7–130.6, 85.3–120.1, 82.1–113.2, 114.8–162.1 and 95.4–134.4 kJmol−1 respectively, whereas Ea determined by using new developed non‐isothermal method was found to be in the range 70.9 to 106.3 kJmol−1.By comparison the activation energies, it has been concluded that new integral method gave the sharp range and consistent value with highest correlation coefficient, indicating that new developed non‐isothermal method is most suitable for determination of kinetic parameters. The kinetic parameters seem to be very helpful in investigating the reaction mechanism of the solid‐state reactions in real system and will give an opportunity to develop the mechanism of the decomposition reaction.