In situ polymerization of aniline on the surface of manganese oxide nanosheets for reducing fire hazards of epoxy

Layered manganese dioxide (MnO2) is a promising nanofillers for reducing the fire hazards of polymeric materials due to its excellent catalytic charring effect. However, its poor dispersion in polymer matrices hindered its full performance. In this work, polyaniline (PANI) coatings were uniformly coated on the surface of MnO2 nanosheets by in-situ polymerization method to form binary hybrids (PANI-MnO2 hybrids). The prepared PANI-MnO2 hybrids were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Scanning electron microscopy (SEM). SEM results of the fractured surface indicated the dispersibility and interfacial interaction between MnO2 and epoxy (EP) matrix were obviously improved, leading to superior fire safety performance of epoxy-based composites. By adding 2 wt% of PANI-MnO2 hybrids, the peak heat release rate (PHRR), total heat release (THR), total smoke production (TSP) and peak smoke production rate (PSPR) values of EP composites were decreased by 34.7%, 37.1%, 44.4%, and 27.0% respectively, compared to those of pure EP. The good dispersion and interfacial interaction of PANI-MnO2 hybrids and the catalysis and physical barrier of MnO2 nanosheets contributed to the superior fire safety performance of EP composites.