Strongly-coupled magnetic nanospheres@trimetallic LDH hooding with thin MXenes veil: Sandwiched ternary nanostructure towards forging fire-safe EP with low toxicity

Transition metals carbides/nitrides (MXenes) have been utilized as flame retardants for epoxy resin (EP) with inherently high fire hazard. However, when the dosage of MXenes is low, the corresponding flame retardant efficiency is hard to meet the demand. Up to now, MXenes-based nanostructure with high flame retardation effectiveness has been rarely investigated. Hence, we have employed the assembly strategy to acquire a sandwiched ternary nanostructure (MX-Fe@LDH), based on strongly-coupled magnetic nanospheres@trimetallic LDH hooding with thin MXenes veil, which has never been reported before. With only 3.0 wt% MX-Fe@LDH dosage, the peak heat release rate, peak CO production rate, peak CO₂ production rate, total CO production are reduced by 51.3%, 70.2%, 49.4%, 74.1%. Comparison with reported works also indicates the high effectiveness of MX-Fe@LDH in flame retardation. The curbed emissions of toxic NO and HCN gases are uncovered via Thermogravimetric analysis-infrared spectrometry test. Postmortem analyses have indicated that using MX-Fe@LDH contributes to engender char with high graphitized degree, which acts as safeguard for basal matrix. Stemming from the rational design, there is a strong mechanical interlocking action between MX-Fe@LDH and EP chains, further prompting the mechanical capabilities. This work may motivate the design of MXenes-based nanostructure towards forging fire-safe polymer composites.