Novel, durably flame-retardant cotton fabrics with fascinatingly restorable fire resistance were prepared by simple grafting of phosphate and melamine, which contributed to a phosphorous-nitrogen (P/N) synergism. During the preparation process, phosphate was grafted with the hydroxyl groups of cellulose to form P-O-C bonds; subsequently, melamine reacted with the aldehyde groups of cellulose generated from phosphorylation to form P/N modified fabrics (P/N-Cotton). The P/N synergistic effect endowed cotton fabric with prominent fire resistance and durability. The Limit oxygen index (LOI) was as high as 51.1 ± 0.3% and was maintained at 32.7 ± 0.8% after 50 laundering cycles (LCs). The total heat release (THR) and peak values of heat release rate (pHRR) of P/N-Cotton were significantly reduced by 70.11% and 64.19%, respectively. Amazingly, the modified cotton fabrics exhibited restorable fire resistance once immersed into the acetic acid solution due to the ion exchange between Na⁺ from detergent and H⁺ from acetic acid. The LOI of P-Cotton and P/N-Cotton after 50 LCs can be restored to 32.4 ± 0.7% and 35.7 ± 0.7% from 20.8 ± 0.7% and 32.7 ± 0.8%, respectively. The analysis of gas-phase products and residual char demonstrated that the incorporation of phosphate and melamine facilitated cellulose fibers to convert to dense and stable graphitized carbon layers and carbon-nitrogen heterocycles, effectively protecting the fabric from decomposing to flammable gases.

通过简单接枝磷酸盐和三聚氰胺制备了具有令人着迷的可恢复耐火性的新型耐用阻燃棉织物，这有助于磷氮 (P/N) 协同作用。在制备过程中，磷酸盐与纤维素的羟基接枝形成POC键；随后，三聚氰胺与磷酸化产生的纤维素醛基反应形成P/N改性织物（P/N-Cotton）。P/N 的协同效应赋予棉织物突出的防火性和耐用性。极限氧指数 (LOI) 高达 51.1 ± 0.3%，并在 50 次洗涤循环 (LC) 后保持在 32.7 ± 0.8%。P/N-Cotton 的总放热（THR）和放热率峰值（pHRR）分别显着降低了 70.11% 和 64.19%。令人惊讶的是，⁺来自洗涤剂，H ⁺来自乙酸。P-Cotton 和 P/N-Cotton 在 50 次 LC 后的 LOI 可以分别从 20.8±0.7% 和 32.7±0.8% 恢复到 32.4±0.7% 和 35.7±0.7%。气相产物和残炭分析表明，磷酸盐和三聚氰胺的掺入促进了纤维素纤维转化为致密稳定的石墨化碳层和碳氮杂环，有效地保护了织物免于分解为易燃气体。