Kinetics Study on Thermal Degradation of Polystyrene and Sulfonated Polystyrene from Styrofoam Waste

Abstract

This research studied the kinetics of the thermal degradation of polystyrene (PS), and sulfonated polystyrene (sPS) which were synthesized from styrofoam waste. The thermal study was conducted by thermogravimetric analysis (TGA) at various heating rates of 10, 15, 20, and 25 dpm. The kinetics parameters were determined by Coats Redfern (CR), Friedman (FM), Kissinger-Akahira-Sunose (KAS), and Ozawa-Flynn-Wall (OFW) models. TGA results showed that PS has a range thermal stability of 274-415o C, but sPS has range thermal stability of 175-582oC. A kinetic study of PS shows that the activation energy increases by increasing fraction conversion for all kinetics parameters with a regression value close to 1. While in sPS, the CR method shows an increase in the activation energy value with an increasing fraction conversion. However, CR-FM-KAS and OFM methods obtained an increase in activation energy, then decreased at the fraction conversion above 0.6 and received negative activation energy. The kinetics model successfully explains the degradation of PS and sPS. Additionally, the high thermal stability of sPS from styrofoam waste shows that this material has good potential as a polymer electrolyte material.