Facile fabrication of high-efficiency reactive flame retardant toward cotton fabric with good hand feeling and high fire safety

High flame-retardant efficiency and good hand feeling are particularly critical in the application of cotton fabrics. Herein, a reactive flame retardant (PAzP) with ammonium phosphate ester groups was designed and bonded to cotton fabric through a dip-pad-cure process. The obtained PAzP-treated fabrics exhibited good hand feeling and high fire safety. The finishing process had no essential effect on the crystal structure of cellulose. With 11.8 wt% PAzP bonded, the attributes of the fabric's texture, including resilience, softness, and smoothness, were nearly indistinguishable from those of pristine fabric. Meanwhile, PAzP-treated fabric achieved a LOI value of 33.3% and self-extinguished immediately after removing the igniter in the vertical burning test. The material exhibited outstanding performance in the cone calorimeter test, demonstrating a remarkable decrease in both heat and smoke release, thus indicating its exceptional fire safety properties. The investigation of char residue and decomposed volatiles confirmed that PAzP functioned as a flame retardant by generating graphitized char residues, which limit the propagation of heat and oxygen and curtailed the emission of flammable volatiles in the condensed phase. Additionally, PAzP released a substantial amount of CO 2 , which mitigated the flammable volatiles and oxygen in the gaseous phase. Overall, this study presents a potential strategy for producing cotton fabric that possesses excellent fire safety and comfortable tactile properties.