An Investigation of the thermal degradation of the intumescent coating containing MoO3 and Fe2O3

An intumescent flame retardant coating was prepared using an ammonium polyphosphate (APP)–pentaerythritol (PER)–melamine (MEL) intumescent flame retardant (IFR) system. Molybdenum trioxide (MoO3) and ferric oxide (Fe2O3) were used as modifiers to improve the thermal stability of the APP–PER–MEL coating. The effects of MoO3 and Fe2O3 on the thermal stability of the residue chars were studied using thermogravimetric analysis (TGA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) and scanning electric microscopy (SEM). The TGA results showed that adding MoO3 and Fe2O3 increased the residue weights of the APP–PER–MEL coatings. XPS analysis demonstrated that the thermal stability of the coatings was improved. SEM images of chars illuminated that MoO3 and Fe2O3 improved the outer and inner surface structure of the residue char layer. All the results indicated that MoO3 and Fe2O3 were effective modifiers to improve the thermal stability of the APP–PER–MEL coating.