Uniformly-Dispersed Black Phosphorene as Flame-Retardant Epoxy Composites via Iterative Dispersion Strategy

摘要

Black phosphorus (BP) nanosheets are widely used in flame retardant polymers, but the challenge of poor dispersion in polymers increases their additions and raises the cost of BP-based flame-retardant materials. Here, we propose an iterative dispersion strategy that gradually approaches a homogeneous dispersion state by separating aggregates and dispersions in the BP partial dispersion with multiple cycles. An iron(III) trifluoromethanesulfonate functionalized BP (BFF) is utilized for the flame retardant and reinforcing modification of the epoxy matrix to verify the reliability of this strategy, noting that the F element in BFF can achieve dynamic hydrogen bonds with the epoxy-amine system during the curing process, further promoting dispersion. Therefore, epoxy thermosets with only 0.2 wt % BFF loading achieve UL-94 V-0 level with a limiting oxygen index (LOI) of 29.2% through the synergistic effect of iterative dispersion and dynamic hydrogen bond. The formation of hydrogen bonds between BFF and the epoxy matrix also contributes to a significant increase in the mechanical properties. This work provides a reasonable and facile concept to achieve sufficient dispersion of inorganic nanosheets in polymer or organic matrices and also promotes the process of industrial large-scale manufacturing of BP-based fire-retardant materials.

关键词