Pyrolysis, kinetic and kinetic model study of epoxidized natural rubber

Abstract

Pyrolysis, kinetics properties and a kinetic model of epoxidized natural rubber (ENR-50) were studied in this work by differential scanning calorimeter (DSC) and thermogravimetry analysis (TGA/DTGA) tests. DSC results indicated that the ENR-50 rubber remained still, without degradation, until 354.65°C and ENR-50 degrades at temperatures ranging between 354.65 to 420°C at a constant heat rate (10°C/min). The degradation enthalpy was (-1241.8 J/g) and the remaining ash was 1.48% at 500°C. Degradation kinetics were studied according to Kissinger, Flynn-Wall-Ozawa, Friedman and Kissinger-Akahira-Sunose methods at different heating rates in nitrogen, at a flow rate of 20 ml/min. Activation energies and the pre-exponential factor were evaluated from the slope of Flynn-Wall-Ozawa, Friedman and Kissinger-Akahira-Sunose plots at conversions between 10 and 90%. The activation energy was also calculated by the Kissinger's method and it was equal to 41.735 kJ mol-1. Criado's method was employed to investigate the kinetic model, g(α;) of ENR-50 and it was found that the diffusion model (D1) agreed with ENR-50 degradation data.