Fire-safe, mechanically strong and tough thermoplastic Polyurethane/MXene nanocomposites with exceptional smoke suppression

Thermoplastic polyurethane (TPU) has been extensively used in many industrial fields because of its excellent mechanical, electrically insulating and chemical/oil-resistant properties. However, it is inherently flammable and produces a huge amount of heat and smoke upon ignition, significantly impeding its industrial applications. Current fire-retardant strategies often result in significantly reduced flammability, but limited contribution to smoke suppression, and even reduced mechanical properties due to different governing mechanisms. To overcome this hurdle, herein, we reported a titanium carbide-derived nanohybrid (Ti3C2Tx-D-H) via simple hydrogen-bonding assembly. Our results show that the peak of heat release rate and total smoke release yield of TPU nanocomposite containing 2.0 wt% Ti3C2Tx-D-H are decreased by 27.3% and 43.8%, respectively, compared to those of pure TPU. Besides, the resultant TPU nanocomposite shows 32.8% and 56.8% increases in tensile strength and toughness, respectively. The distinguished fire-resistance and mechanical performances are ascribed to the tortuous effect, catalyzed charring and free radicals quenching function of Ti3C2Tx-D-H nanohybrid together with a favorable TPU-Ti3C2Tx-D-H interface. This work offers a promising strategy for simultaneously enhancing the fire resistance, smoke suppression and mechanical robustness of TPU, which is expected to find more industrial applications.