Synergistic effects of aryl diazonium modified Few-Layer black Phosphorus/Ultrafine rare earth yttrium oxide with enhancing flame retardancy and catalytic smoke toxicity suppression of epoxy resin.

[Display omitted] • Few-layer black phosphorus was prepared via a simple hydrothermal Li+ intercalation method. • Aryl diazonium modified black phosphorus/ ultrafine yttrium oxide promisingly reduced the fire hazard of epoxy resins. • The possible mechanism of radical removal and catalytic carbonation was put forward. • This work might have a promising prospect for developing efficient covalent functionalized BP nanocomposites. Black phosphorus (BP), as a promising star of two-dimensional (2D) van der Waals family, has attracted extensive attention for its characteristic dimension effects, mechanical properties and thermal stability. Herein, we report a facile strategy of integrating aryl diazonium modified few Layer black phosphorus with loading of ultrafine yttrium oxide (BP-NH-Y), for reducing the fire hazard of epoxy resin (EP). The results of cone calorimetry test results manifest that the flame retardancy of EP can significantly improve by adding 2 wt% BP-NH-Y, for instance, the peak heat release rate (pHRR) and the total heat release (THR) is reduced by 47.0% and 48.1%, respectively. Especially, adding the BP-NH-Y nanosheets distinctly inhibite the diffusion of EP pyrolysis products (such as toxic CO, hydrocarbons etc.) during flaming. In particular, epoxy composites with only 1.0 wt% BP-NH-Y were able to achieve UL-94 V-0 rating with an oxygen index of more than 30. This work may have a promising prospect for developing efficient covalent functionalized BP nanosheets to meet the needs of sustainable applications. [ABSTRACT FROM AUTHOR]