Novel phytate-piperazine-melamine intumescent flame retardants for high-performance polyurea composite

Traditional intumescent flame retardant (IFR), typically composed of 2–3 flame retardants, have been widely used. However, they tend to weaken the mechanical performance of polymer-matrix composite and have a time-consuming compounding process. Here, a novel three-in-one IFR was synthesized via a self-assembly strategy. The three-in-one IFR was designed in which the ratios of phytic acid, piperazine and melamine were 1:3:3, 1:4:2 and 1:5:1, respectively, and they were named as PPM-1, PPM-2, and PPM-3. Additionally, their effects on the flame retardancy and mechanical properties of polyurea (PUA) composites were systematically investigated. Although they have the same ingredients, their performances are vastly different. Among the PPM, PPM-2 was found to exhibit exceptional performance. When 25.0 wt% of PPM-2 nanoparticle was incorporated into PUA, significant reductions in peak heat release rate (67.2 %), total heat release (19.9 %), and total smoke production (42.9 %) were observed. The mechanisms behind different fire safety and mechanical performance have been revealed with variations of microscale morphology and chemical decomposition. This work presents a practical strategy for utilizing nano-particles in soft protective structures, which is also expected to significantly benefit the development of three-in-one IFR.