High anti-ablative epoxy resin-based flame retardant and thermal insulation coating based on spontaneous Ceramization and vitrification

In order to improve the burn-through resistance and environmental friendliness of epoxy resin-based flame-retardant coatings, high-performance coatings were developed by modifying them with silicone resin and B4C. By incorporating B4C and silicone resin, the coating's thermal stability was significantly enhanced. By participating in a series of chemical reactions when the coating was exposed to fire, they promoted spontaneous ceramicized and vitrified modification, increased the mass of char residue, improved the surface compactness, optimized the foam structure, and improved the specific surface area of char residue. Compared to blank sample E10S0 and others, E85S15B3 coating co-modified with silicone resin and B4C showed the best performance. The backside temperature of E85S15B3 was only 164.34°C after a 2 h combustion test. The peak heat release rate (PHRR), total heat release rate (THR), total smoke production (TSP), peak smoke production rate (PSPR), peak CO release rate (PCOPR), and peak CO2 release rate (PCO2PR) of E85S15B3 were all significantly improved, with a decrease of 20.38 %, 40.06 %, 37.67 %, 49.21 %, 64.71 %, 0.03 % compared with that of E10S0 sample. The LOI value was 34.6 %, which was 48.24 % better than that of E10S0. Moreover, the compressive, tensile, and bending strengths of E85S15B3 were measured at 85.6 MPa, 25.6 MPa, and 45.3 MPa, respectively, marking a 22.1 % increase, 11.23 % increase, and 23.19 % increase over those of E10S0. The mechanism of flame-retardant includes cooling insulation, non-flammable gas-phase dilution flame retardancy, condensed phase physical insulation, reinforced-phase flame retardancy, and free radicals capturing to block combustion.