A novel flame retardant containing phosphorus and nitrogen elements, ammonium salt of N,N-dimethylene p-benzenesulfonic phosphonic acid (ADBSPA), was prepared by one-step continuous chemical method. The chemical structure of the ADBSPA was determined by nuclear magnetic resonance spectrum (NMR) and Fourier transform infrared (FTIR), and ADBSPA was processed onto cotton materials by immersion method. The flame retardancy of coated cotton materials was analyzed by limiting oxygen index (LOI) and Vertical burning test. The LOI value of cotton coated with 350 g/L ADBSPA increased from the original 18.2 ± 0.2% to 31.7 ± 0.2%, and the damaged length of this sample reduced to 6.6 ± 0.1 cm, which proved that ADBSPA enhanced the anti-burning ability of cotton materials. Cone calorimetry was used to evaluate the combustion behavior of cotton materials before and after coating. Compared with original sample, ADBSPA changed the combustion path of cotton materials, and the intuitive performance was that the ADBSPA-cotton-4 reserved 25.1 ± 0.5% of char residue at 250 s, and its peak heat release rate (PHRR) greatly reduced to 17 ± 1 kW/m². The surface morphology of uncoated and coated cotton materials was characterized by scanning electron microscopy (SEM). It was observed that the coated sample still maintained a complete fiber skeleton after burning. In addition, thermogravimetric (TG) analysis confirmed that the coated cotton materials had good thermo-oxidative and thermal stability. All results pointed out that the phosphorus and nitrogen elements contained in ADBSPA as well as cotton cellulose constituted the three basic conditions of intumescent flame-retardant system. The polyphosphoric acid compounds formed by phosphorus element at high temperature promoted the dehydration of cotton fibers into char layer. The non-flammable gases produced by the nitrogen element in the combustion process covered the surface of fabrics, thereby playing the role of shielding heat and diluting combustible gases.

Graphic abstract

A novel phosphorus-nitrogen flame retardant was prepared by one-step continuous chemical method and applied to improve the thermal stability and anti-flammability of cotton materials.

中文翻译：

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一种一步法合成棉材料的新型P / N基阻燃剂及其阻燃机理

通过一步连续化学法制备了一种新型的含磷和氮元素的阻燃剂，N，N-二亚甲基对苯磺酸膦酸铵盐（ADBSPA）。通过核磁共振谱（NMR）和傅立叶变换红外光谱（FTIR）确定了ADBSPA的化学结构，并通过浸没法将ADBSPA加工到棉料上。通过极限氧指数（LOI）和垂直燃烧试验分析了包覆棉材料的阻燃性。涂有350 g / L ADBSPA的棉花的LOI值从原始的18.2±0.2％提高到31.7±0.2％，样品的损坏长度减少到6.6±0.1 cm，这证明ADBSPA增强了抗燃能力棉花材料。锥量热法用于评估包衣前后棉花材料的燃烧行为。与原始样品相比，ADBSPA改变了棉质材料的燃烧路径，直观的性能是ADBSPA-cotton-4在250 s时保留了25.1±0.5％的残炭，其峰值放热率（PHRR）大大降低至17±1千瓦/米²。通过扫描电子显微镜（SEM）表征未涂覆和涂覆的棉材料的表面形态。观察到，涂覆的样品在燃烧后仍保持完整的纤维骨架。另外，热重（TG）分析证实涂覆的棉材料具有良好的热氧化和热稳定性。所有结果表明，ADBSPA中所含的磷和氮元素以及棉纤维素构成了膨胀型阻燃体系的三个基本条件。磷元素在高温下形成的多磷酸化合物促使棉纤维脱水成炭层。氮元素在燃烧过程中产生的不可燃气体覆盖了织物的表面，

图形摘要

通过一步连续化学法制备了一种新型的磷氮阻燃剂，并用于提高棉材料的热稳定性和阻燃性。