Synthesis of melamine cyanuric based flame retardant via hydrogen bond self-assembly and in-situ dispersion strategies for improving comprehensive performance of epoxy resin

The design of flame retardant epoxy resin (EP) with superior smoke suppression, mechanical properties and simple manufacturing process has been very challenging in industry and academia. Herein, we synthesized an amino-rich polyphosphazonitrile microsphere (PZS) to regulate the synthesis of melamine cyanurate (MCA) through hydrogen bond self-assembly and in-situ dispersion strategies for flame retardant EP. The in-situ dispersion strategy effectively alleviates the agglomeration of PZS@MCA assembly units by taking advantage of the viscosity of EP prepolymer. The hydrogen bond self-assembly strategy provides a strong P/N synergistic effect for MCA. Combined with the in-situ dispersion strategy, adding only 9 wt% PZS@MCA can achieve the UL-94 V-0 rating with a total smoke production (TSP) values of 21.1 m2. Besides, EP/PZS@MCA-I maintains superior mechanical properties due to larger aspect ratio, abundant terminal functional groups and better dispersion of PZS@MCA.