A novel ceramifiable epoxy composite with enhanced fire resistance and flame retardance

Abstract: A novel epoxy composite with flame retardance and fire resistance was prepared by adding silicate glass frit (SGF) and ammonium polyphosphate (APP) into the epoxy resin. In the combustion test, epoxy composites displayed obvious flame retardance feature, showing much lower heat release rate, total heat release and total smoke production than epoxy resin. The composite residue formed at 900 °C had a flexural strength of 19.05 MPa. In addition, possible mechanisms for the phase separation and crystallization reactions at high temperatures were also investigated in detail through thermogravimetric analyzer, X-ray diffraction, X-ray photoelectron spectrometer, and scanning electron microscopy. It was suggested that phosphorus element tends to migrate to the surface of the composite residue during firing process, and sodium element from SGF is selectively combined with the phosphorus element to obtain crystalline phases. With this unique phase separation and crystallization reactions, the fire resistance of the epoxy composite was significantly improved. Graphical abstract: [Figure not available: see fulltext.].