Interfacial engineering strategy inspired MXenes based nanostructure enabling fire-safe epoxy composite

The widespread application of epoxy resin (EP) is limited by its inherent high fire hazard, primarily attributed to its substantial release of heat and the generation of toxic byproducts during combustion. The usage of 2D material of titanium carbide (MXenes, defined as MX) has been confirmed to show potentials in flame retardation. However, the flame-retardant efficiency of MX is relatively-low. Thus, the interfacial engineering strategy is employed for in-situ development of MoS₂ nanoflakes on MX surface, acquiring the product of MX@MoS₂, which shows the higher interfacial interaction with EP matrix and dispersion stability. By only using 1.0 wt% MX@MoS₂, the PHRR and THR are obviously decreased by 35.8 % and 38.0 %, respectively. Notably, the addition of 3 % MX@MoS₂ results in a higher PHRR reduction 49.4 %. Meanwhile, the PSPR and TSP have reduced by 48.6 % and 36.9 %. Such results indicate the enhanced flame retardance, benefiting from the physical barrier and chemical catalyst roles of MX@MoS₂. Of note, the peak CO and CO₂ yields are decreased by 53.3 % and 57.2 %. Upon exposure to heat source, MX@MoS₂ promotes the formation of dense, thermally-stable char layer, which effectively insulates the underlying polymer, slows down thermal and material transport, and impairs the volatile emissions. It is satisfying to find that the mechanical characteristics of EP composites are enhanced after adding MX@MoS₂. This study offers ideas to produce an extremely efficient MX-based flame retardant, extending the applications of composites made of polymers.