Thermal and pyrolysis analysis of minerals reinforced intumescent fire retardant coating

This study presents the results of intumescent fire retardant coatings (IFRCs) developed to investigate the synergistic effects of mineral fillers (clay and wollastonite) based IFRC towards heat shielding, char expansion, morphology, composition, gaseous products and residual weight. The fire test has been performed to study the heat shielding effect of IFRCs on the substrate using UL-1709 standards. The results showed the synergistic effect of clay and wollastonite using 5 wt.% enhanced the fire protection, performance with recorded substrate temperature 113 °C after 1-h fire test. Field Emission Scanning Electron Microscopy (FESEM) and High-Resolution Transmission Electron Microscopy (HRTEM) showed the micrograph of compact char structure that increased char integrity due to the presence of inorganic fillers. X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) results showed the presence of boron phosphate, silicon phosphate oxide, aluminum borate in char that improved the thermal performance of IFRC up to 800 °C. X-Ray Photoelectron Spectroscopy (XPS) confirmed that 5 wt% (IFRC-5) of clay and wollastonite increased the carbon content up to 50.67%, lowering oxygen content to 27.73% in the char that enriched the fire resistance performance of the coating. Pyrolysis-Gas Chromatography-Mass Spectrometry (Pyrolysis GC-MS) confirmed that formulations IFRC-5 released less gaseous product concentration compared to IFRC-C and maximum reduction in gases was recorded from 3.4e+07 to 1.08e+07. Thermogravimetric analysis (TGA) demonstrated in residual weight was increased to 46.45% for IFRC-5 which resulted in the high thermal stability of the coating.