Flame retardant and anti-corrosion epoxy resin with strong mechanical property enabled by P/N/S ionic compound

Optimal epoxy resin materials need to have a combination of excellent properties on flame retardance, smoke suppression, transparency and mechanical strength. However, the current strategy in the design for flame retardants tends to improve flame retardancy, while often accompanied by other performance deterioration. Herein, an ionic compound (A-D) verified with X-ray diffraction technology was synthesized by a simple acid-base neutralization reaction, and applied as a flame retardant agent for EP. EP/A-D thermoset showed good flame retardancy, confirmed by a high limiting oxygen index (LOI) of 36.5 % and a UL-94 V-0 rating when A-D addition was 6 %.The total smoke production (TSP) and total heat release rate (THR) decreased by 65.3 % and 41.9 % when compared with pure EP. The obvious decrease of TSP and THR was contributed to the radical capturing and catalytic charring endowed by A-D. Furthermore, EP/6A-D exhibited outstanding mechanical properties, the tensile strength and flexural strength of EP/6A-D increases by 40.4 % and 150.4 %, respectively, compared to pure EP. Such a strong mechanical strength has hardly been found in the modified EP reported in literatures. Furthermore, the EP composite also has good transparency, and better resistance to corrosion. The excellent overall properties endow EP/6A-D composites great potential for enlarging epoxy composites applications.