“…One proposed solution to this problem is the development of flame retardants [ 11 , 12 , 13 , 14 ], which could restrain the ignition and fire-spreading of polymer materials, specifically decreasing heat release and smoke production. To date, various flame retardants have been developed to achieve satisfactory fire resistance in different polymer materials, such as halogenated flame retardants [ 15 , 16 , 17 , 18 , 19 ], inorganic layered compounds [ 20 , 21 , 22 , 23 ], and phosphorous–nitrogen intumescent flame retardants [ 24 , 25 , 26 , 27 ]. Flame-retardant polymers and their composites have been used widely in construction, electronics, transportation, and so on [ 28 , 29 , 30 ].…”