Utilization of renewable materials for the development of safer and nontoxic flame retardants has been of interest from environmental safety and sustainability perspective. Tannic acid (TA) is an abundantly available bio-based polyphenol that exhibits good intumescence and char forming characteristics upon being subjected to heat. Intumescence and char formation are important prerequisites for certain types of effective flame retardant (FR) additives. However, the potential for utilizing TA as an FR has been limited by its poor thermal stability. A single step chemical modification process that overcomes the limitations of TA while allowing the utilization of its beneficial properties is reported here. TA was crosslinked using interfacial polycondensation with terephthaloyl chloride to yield tannic acid terephthalate (TAT). The complex structure of TAT necessitated the synthesis of several model compounds based on methyl gallate (MG) to facilitate the complete structural characterization of TAT using FTIR and ¹H NMR. TAT is thermally stable up to 230 °C (less than 3% weight loss) and shows 30% higher char yield and extremely low heat release capacity (<80 J/g-K) as compared to that for TA. Detailed thermal degradation studies combined with gas phase spectroscopy using thermogravimetric analysis - Fourier-transform infrared spectroscopy (TGA-FTIR) and pyrolysis - gas chromatography - mass spectrometry (Py-GC-MS) provide an understanding of the degradation process. Crosslinked phenolic species enhance char formation in the condensed phase and allow for utilization of these compounds as flame retardant coatings for polymers such as Nylon 6,6. TAT coating on Nylon 6,6 fabric significantly impedes flame propagation in the fabric, resulting in quick self-extinguishing behavior and reduced char length in vertical flame tests. Morphological characterization, thermo-oxidation studies and microscale combustion calorimetry (MCC) (at high heating rates) of TAT-coated fabric reveal the beneficial effects of char formation and its direct impact on flame retardancy.

从环境安全和可持续性的角度来看，利用可再生材料开发更安全和无毒的阻燃剂已引起人们的兴趣。单宁酸（TA）是一种可大量获取的生物基多酚，在受热时具有良好的膨胀性和成炭特性。膨胀和形成炭是某些类型的有效阻燃（FR）添加剂的重要先决条件。但是，将TA用作FR的潜力受到其热稳定性差的限制。本文报道了克服TA局限性同时允许利用其有益特性的一步化学修饰工艺。通过与对苯二甲酰氯的界面缩聚反应将TA交联，生成单宁酸对苯二甲酸酯（TAT）。^1个1 H NMR。与TA相比，TAT在高达230°C的温度下（小于3％的重量损失）具有热稳定性，并显示出高30％的炭收率和极低的放热能力（<80 J / gK）。详细的热降解研究与结合使用热重分析的气相色谱-傅立叶变换红外光谱（TGA-FTIR）和热解-气相色谱-质谱（Py-GC-MS）一起，可以了解降解过程。交联的酚类物质可增强缩合相中的焦炭形成，并允许将这些化合物用作聚合物（如尼龙6,6）的阻燃涂料。尼龙6,6织物上的TAT涂层显着阻碍了火焰在织物中的传播，从而导致了快速的自熄性，并缩短了垂直火焰测试中的炭长度。形态表征