Growth of biobased flakes on the surface and within interlayer of metakaolinite to enhance the fire safety and mechanical properties of intumescent flame-retardant polyurea composites

In this work, meta-kaolinite has been successfully multidimensionally modified by growing melamine-phytate nanoflakes within the interlayer and on the surface of metakaolinite via facile and green supramolecular self-assembly technology. Then, multidimensionally modified metakaolinite (Mul-K₀) along with intumescent flame retardant (IFR) has been incorporated into polyurea (PUA)The incorporation of Mul-K₀ together with IFR into PUA has simultaneously enhanced both the fire safety and mechanical property. Flame retardancy and smoke suppression of Mul-K₀ based PUA/IFR composite have been evaluated by oxyacetylene ablation test, limiting oxygen index, UL-94 vertical burning and conventional or modified cone calorimeter tests. The underlying mechanism of Mul-K₀ responsible for enhancing the fire safety and mechanical properties were explored. This work offers a new strategy for improving the flame-retardancy efficiency utilizing the synergistic effect of IFR and modified meta-kaolinite and provides a promising opportunity for fabricating long-life flame retardant PUA composites.