Organic-inorganic hybrid engineering MXene derivatives for fire resistant epoxy resins with superior smoke suppression

It is a challenge to integrate organic and inorganic materials to build organic–inorganic hybrid, high-efficiency flame retardants with synergistic effects of both to diminish the fire risks of polymer composites. In this work, an organic–inorganic hybrid strategy was used to prepare leaf-like MXene-based flame retardants ([email protected]) by in situ growth of bimetallic metal–organic frameworks (Bi-MOF) on the surface of MXene and the hybrids were incorporated into epoxy resins to explore their flame retardancy and smoke suppression effects. Specifically, the introduction of [email protected] hybrids not only achieved homogeneous dispersion in EP matrix, but also improved the thermal properties of EP composites, with a 27.7% lower maximum mass loss rate (Rmax) than that of pure EP. In addition, EP composites containing 2 wt% [email protected] exhibited improved fire safety, reduced heat release and inhibited smoke production, as evidenced by a 28.8%, 45.3%, 36.5%, 30.7% and 55.3% drop in peak heat release rate (PHRR), peak smoke production rate (PSPR), total heat release (THR), peak CO production rate (PCO) and smoke factor (SF) value, respectively, as well as growing char yields and lower fire growth index (FGI) value, compared to those of pristine EP. The synergistic action of MXene and Bi-MOF, mainly including the blocking effect of MXene lamellar structure, catalytic carbonization effects as well as catalytic attenuation of the transition metal oxides and gas phase dilution from Bi-MOF, was primarily responsible for the improved fire safety of EP composites.