Intumescent fire-retardant performance and small-scale reaction mechanism on banana/bio-epoxy composites

The present work deals with the thermal degradation, the physical characterization, and kinetic mechanisms of green epoxy resin-based biocomposites (BC) reinforced by banana leaf fiber (BLF). The two main samples have been manufactured using the vacuum bag resin transfer molding method. The first, BLF-based BC, is used as a control sample, while the second sample is coated with 6% wt. of intumescent fire retardant (IFR), which contains APP and boric acid. The effect of IFR coating has been investigated using thermogravimetric analysis (TGA) under inert and oxidative atmospheres and kinetic studies of model-free and model-based approaches have been applied for predicting the kinetic parameters of thermal degradation reactions. The TGA results show that the IFR coating delays the thermal degradation around 13–20 K of BLF-based BC materials, which leads to an increase of 8% in the char residue under inert atmosphere. In addition, the sample has been characterized by SEM, EDS, and FTIR analysis (before and after the TGA test). The effectiveness of the IFR protective role is displayed on the SEM micrographs by showing the hole of the char enclosed and built the foam layer. The kinetic parameters from model-free and model-based curve fitting of BLF-based BC and BLF-based BC-coated IFR are obtained, while the effect of IFR on the kinetic parameter increased the activation energy (model-free and model-based) under inert atmosphere. The fitting methods and optimization procedure gave excellent results for kinetic parameters, showing a particularly good correspondence with the TGA experimental data.