Traditional flame retardants, often derived from petrochemical sources, pose significant environmental and health concerns due to their potential toxicity and persistence in the environment. In this study, a biobased hyperbranched polymer flame retardant named QB was synthesized using quercetin and phenylphosphoryl dichloride by a one-step method. The QB copolymer was characterized via Fourier transform infrared spectroscopy, thermogravimetric analysis, and gel permeation chromatography, revealing its high thermal stability and polymeric nature, with a weight-average molecular weight of 78 299 g/mol. QB was subsequently incorporated into bisphenol A-type epoxy resins using 4–4 diamino diphenylmethane as a curing agent to prepare the flame-retardant epoxy composite. With additions of only 1 wt % QB, EQB-1 achieved a UL 94 V-0 rating in the vertical burning test and an impressive limiting oxygen index (LOI) value of 28.2%. Moreover, the addition of the 3 wt % QB in EP resulted in a maximum reduction of 32.9% in the peak of heat release rate and a 37.4% reduction in the smoke produce rate, indicating its outstanding flame-retardant and smoke suppression properties, which are attributed to a mainly condensed-phase flame-retardant mechanism. Furthermore, the impact and flexural strength of the composite were maintained and a slight improvement was observed. The findings of this research are expected to contribute to the development of environmentally friendly flame-retardant epoxy systems that meet industry standards while promoting the use of renewable materials. This work supports sustainability by replacing petrochemical flame retardants with renewable quercetin-based materials, reducing toxicity and environmental impact.

中文翻译：

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源自槲皮素的高效超支化阻燃剂，用于环氧树脂，具有均衡的综合性能


传统的阻燃剂通常来自石化产品，由于其潜在的毒性和在环境中的持久性，会带来重大的环境和健康问题。在本研究中，使用槲皮素和苯基磷酸基二氯化物通过一步法合成了一种名为 QB 的生物基超支化聚合物阻燃剂。通过傅里叶变换红外光谱、热重分析和凝胶渗透色谱对 QB 共聚物进行了表征，揭示了其高热稳定性和聚合物性质，重均分子量为 78 299 g/mol。随后，以 4–4 二氨基二苯基甲烷为固化剂，将 QB 掺入双酚 A 型环氧树脂中，制备阻燃环氧树脂。EQB-1 仅添加 1 wt % QB，在垂直燃烧测试中达到 UL 94 V-0 等级，并达到令人印象深刻的 28.2% 极限氧指数 （LOI） 值。此外，在 EP 中添加 3 wt % QB 导致热释放速率峰值最大降低 32.9%，发烟速率降低 37.4%，表明其出色的阻燃和抑烟性能，这归因于主要的冷凝相阻燃机制。此外，复合材料的冲击强度和弯曲强度保持不变，并观察到略有改善。这项研究的结果有望有助于开发符合行业标准的环保阻燃环氧树脂系统，同时促进可再生材料的使用。这项工作通过用可再生槲皮素基材料取代石化阻燃剂来支持可持续性，从而降低毒性和环境影响。