Polyacrylonitrile (PAN) is utilized as a precursor for the production of high-performance flame retarding fibers and is also widely used for clothing fibers. Herein, we report the flame retarding properties of catechol-containing PAN copolymers. The comonomer, dihydroxy styrene (DHS), was prepared from bio-derived caffeic acid (CA), which is a key intermediate in the biosynthesis of lignin. P(AN-co-DHS) and P(AN-co-CA) were synthesized by free radical polymerization. The effect of the comonomer structure on the stabilization of PAN copolymers was studied by differential scanning calorimetry, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The catechol and acid groups of P(AN-co-DHS) and P(AN-co-CA) are effective at lowering the activation energy (E_a) for cyclization of the AN through an ionic mechanism. In CA copolymers, the acid-protected poly(acrylonitrile-co-methyl caffeate) (P(AN-co-MCA)) was found to be the most efficient in terms of E_a, the extent of reaction, and char fraction. The microscale combustion calorimetric analysis after thermal treatment (300 °C, 3 min) showed that the limiting oxygen index and heat release capacity of the P(AN-co-MCA₃) fiber were approximately 45% with V-0 of UL rating (superior to Nomex®) and 63 J g⁻¹ K⁻¹, respectively. This research demonstrates a simple, sustainable methodology for the production of environmentally friendly and high-performance flame retardants.

中文翻译：

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含生物源性咖啡酸衍生物的热氧化聚丙烯腈共聚物的高效无卤阻燃剂

聚丙烯腈（PAN）用作生产高性能阻燃纤维的前体，也广泛用于服装纤维。在此，我们报道了含邻苯二酚的PAN共聚物的阻燃性能。共聚单体二羟基苯乙烯（DHS）是由生物衍生的咖啡酸（CA）制备的，而咖啡酸是木质素生物合成的关键中间体。P（AN-共聚-DHS）和P（AN-共聚-CA）通过自由基聚合来合成。通过差示扫描量热法，傅立叶变换红外光谱法和热重分析法研究了共聚单体结构对PAN共聚物稳定性的影响。P（AN- co -DHS）和P（AN- co）的儿茶酚和酸基-CA）有效地降低了通过离子机理使AN环化的活化能（E _a）。在CA共聚物中，发现酸保护的聚（丙烯腈-共-甲基咖啡酸酯）（P（AN-共-MCA））就E _a，反应程度和炭含量而言是最有效的。热处理（300°C，3分钟）后的微量燃烧量热分析表明，P（AN - co- MCA ₃）纤维的极限氧指数和放热能力约为45％，UL等级的V-0为（优于Nomex®）和63 J g ^-1 K ^-1， 分别。这项研究证明了生产环保和高性能阻燃剂的简单，可持续的方法。