Determination of kinetic parameters and thermal decomposition of Epoxy-Moringa gum biocomposite using thermogravimetric analysis

Abstract

The use of natural filler based composites in various applications is growing due to easy availability and eco-friendly nature of the natural fillers. In the present study, an epoxy based bio composite has been prepared using Moringa oleifera gum as bio filler in order to investigate thermal properties. The composites have been prepared by incorporating Moringa oleifera gum at different volume fractions (4%, 8%, 12%, 16%, 20% v/v). Hand layup technique is used to fabricate the composite material. Fourier Transform Infrared Spectroscopy confirmed the formation of epoxy Moringa gum composite. Using thermogravimetric analysis data, activation energy and regression values (R²) for the second stage of epoxy Moringa composite degradation have been determined by Coats-Redfern integration methods which involves 13 different kinetic models. The energy of activation is in the range of 72 to 99 kJ/mol and frequency factor was in the range of 2.5x10⁵ to 7.69x10⁷ for second order model which was identified as the best fitted model with R² value close to 1. The results are also compared with Broido and Horowitz-Metzger models. As the volume percentage of Moringa gum increases, the activation energy, frequency factor, enthalpy, entropy and Gibbs free energy also increases which proves the thermal stability of the Epoxy Moringa gum biocomposite is superior to the epoxy resin. Thus Moringa gum can be used as a potential bio filler to produce gum based composites having high thermal stability and can be promoted widely in various engineering applications.