Facile strategy to synthesize MXene@LDH nanohybrids for boosting the flame retardancy and smoke suppression properties of epoxy

The creation of high-efficient MXene-based flame retardants to cope with the fire hazards of polymer composites remained an intractable challenge. Hence, this work explored a facile strategy to synthesize MXene-based nanohybrids ([email protected]) by in situ growth of layered double hydroxides (CoAl-LDH) on the surface of MXene in anticipation of constructing an efficient flame retardant system. The results indicated that the integration of LDH prevented the stacking of MXene nanosheets and enhanced the dispersion of MXene in EP matrix, endowing EP composites with excellent thermal properties and flame retardancy. With the addition of 2 wt% [email protected], EP composites exhibited reduced the maximum mass loss rate (Rmax) of 28.5%, increased residual char and led to 25.3% reduction in PHRR and a drop of 24.4% in THR, compared to those of neat EP. Furthermore, EP/2 wt% [email protected] composites also demonstrated superior smoke suppression performance, mainly reflected by the 38.5%, 37.8%, 33.8% and 31.2% reduction in PSPR, TSP, PCO and PCO2, respectively, together with a 52.0% decline in smoke factor (SF), compared to those of pure EP. The improved fire safety of EP composites was attributed to the catalytic charring and attenuation effect of the transition metal oxides, coupled with the barrier effect of the nanosheets and the cooling effect, gas-phase dilution effect of LDH.