Synthesis of a novel phosphazene derivative and its application in intumescent flame retardant-EVA copolymer composites

A novel phosphazene derivative, hexakis(dodecylamino)cyclotriphosphazene (H-12), was synthesized and characterized by Fourier-transform infrared (FT-IR), 1H and 31P nuclear magnetic resonance spectroscopy, and elemental analysis. H-12 was applied to an intumescent flame retardant-ethylene-vinyl acetate copolymer (EVA) composite as a synergist and compatibilizer. Integrated flame retardancy performance and good mechanical properties could be achieved simultaneously. The results indicated that H-12 can improve the compatibility of the IFRs with the EVA matrix, and enhance the flame retardancy of the composite. By replacing a portion of the IFRs with 10 wt% H-12, the LOI of the sample reached 29.1%, which is much higher than the pure EVA or its IFR composite. Furthermore, the heat release rate, total heat release, smoke production rate, and total smoke production were greatly decreased. In addition, the improved mechanical properties and the rheological measurement results indicate that H-12 can serve as an efficient lubricant and compatibilizer between the additives and EVA, endowing the materials with satisfactory processability.