Functionalizing Ti3C2Tx for enhancing fire resistance and reducing toxic gases of flexible polyurethane foam composites with reinforced mechanical properties

•ZIF-8@Ti3C2Tx was synthesised and applied to prepare flame-retardant flexible polyurethane foam composites.•Flame-retardant flexible polyurethane foam composites displayed excellent heat and toxic gases suppression performance.•Flame-retardant flexible polyurethane foam composites showed notable mechanical properties during compression and tensile tests.•The flame-retardant mechanism of ZIF-8@Ti3C2Tx was systematically explored through gas and condensed products.