Enhanced residue stability and strength of epoxy-based coating for fire protection via ceramifiable strategy

A combination of talc and ammonium polyphosphate (APP) was used to fabricate the novel epoxy-based fire resistive coatings via ceramifiable strategy designed for steel substrates. The effects of individual and various combinations of fillers on the fire protection, dimensional stability and strength of coating residues fired at high temperatures were evaluated. The optimized formulation (ETA₄) exhibited much lower heat release rate, total heat release and smoke production rate, indicating good flame retardance feature. The results of fire protection test indicated that the backside temperature of steel substrate with ETA₄ coating decreased significantly (below 200 °C). After firing at 1000 °C, creamic-like foam residue was formed and it showed excellent dimensional stability and good mechanical strength. Furthermore, the possible fire resistive mechanisms of coatings at high temperatures were also proposed by performing different measurements. The decomposition products of APP-cohered talc were obtained at high temperatures, accompanied by the gradual disappearance of talc phase and generation of crystallization reaction. Finally, a ceramic-like residue was formed, leading to enhanced stability of coating residues.