Phosphorus-containing imidazole derivatives in flame retardancy and curing of epoxy resin Available to Purchase

Synthesizing and developing flame retardants with good miscibility, curing ability, and reinforcing effects simultaneously represents a new frontier in epoxy-based composites. In this regard, phosphoramide-containing imidazole-based compounds have garnered significant attention due to their capability to simultaneously achieve good flame retardancy, reinforcement, and environmental compliance. In this study, a phosphoramide containing imidazole (PI) was synthesized as a model flame-retardant agent. The product was characterized and verified using Fourier transform infrared, ¹H nuclear magnetic resonance (NMR), ¹³C NMR, ³¹P NMR, mass spectrometry, and elemental analysis. The synthesized flame retardant was in a liquid state and exhibited good miscibility with the epoxy resin at room temperature. Curing kinetics, thermal stability, and mechanical properties of the flame-retardant modified epoxy (epoxy/PI) were investigated and compared with 1-(3-aminopropyl)-imidazole (I) modified epoxy resin (epoxy/I), which served as its constituent material. The results demonstrated that the thermal stability and flame retardancy of the epoxy resin were significantly improved in the presence of the synthesized flame-retardant. However, the findings indicated that these flame-retardant materials, while capable of curing epoxy resin on their own, are not sufficient, highlighting the need for additional curing agents to achieve the desired level of curing and enhance the final product’s strength.