A bio-resourced mannitol phospholipid ammonium reactive flame retardant for cotton with efficient antiflaming and durability

Bio-resourced mannitol was employed to synthesize eco-friendly ammonium salt of mannitol hexaphosphate acid ester (AMHPE) by facile, solvent-free tactics. Limiting oxygen index (LOI) of cotton treated with 20–30% AMHPE reached 36.0–42.3% to obtain high-efficiency flame retardancy. After 50 laundering cycles, the LOI value of 30% AMHPE treated cotton still retains an LOI value of 27.9%, revealing outstanding durability owing to new P–O–C covalent bonds formed bewteen –P = O(ONH₄)₂⁺ groups of AMHPE and cotton. The decomposition temperature of treated cotton was significantly lowered and its char residue was much higher than control cotton in N₂. The PHRR and THR values of treated cotton were notably declined to 93.41% and 56.54% respectively, and the residual is 28 times higher by contrast. The combustion products and flame retardant mechanism of treated cotton were analyzed by TG-IR and cone calorimetry. These results indicate that AMHPE flame retardant cotton has acquired efficient flame retardancy, excellent durability and thermostability.

Solvent-free synthesis of bio-resourced N–P synergetic flame retardant possessing excellent flame retardancy, unexceptionable durability and thermostability to reduce cotton fire hazard.