The poor impact toughness and flame retardant performance have greatly restricted the engineering application of epoxy thermoset. To obtain the high-performance epoxy composites, the renewable vanillin-based flame retardant toughening agent (PVSi) was synthesized and incorporated into epoxy. The use of PVSi macromolecules can significantly enhance the impact toughness of epoxy. With 5 wt% of PVSi, the impact strength of the epoxy was maximally raised by 189.69%, from 12.42 kJ/m² of the neat EP to 35.98 kJ/m² of EP/PVSi₅ composites. The toughening effect of PVSi macromolecules on epoxy was closely linked to its structural features, such as the flexible phenylsiloxane, active imine and polar phosphaphenanthrene groups. Simultaneously, the EP/PVSi₅ composites reached up to the V-0 rating in vertical burning test (UL-94) and 29.5% in limiting oxygen index (LOI), with only 0.27 wt% ultra-low phosphorus loading. Additionally, the suppressed heat release, the evidently reduced toxic pyrolytic volatiles, and the promoted charring capability of EP/PVSi composites can be obtained, with phosphaphenanthrene, phenylsiloxane and diaminodiphenylsulfone groups in PVSi macromolecules jointly playing a role. These results indicated the improved fire safety of epoxy. Furthermore, the free radical scavenging effect of P· and PO·, the fuel dilution effect of nonflammable NH₃ and SO₂, the catalytic charring effect of the pyrophosphoric acid and metaphosphoric acid, the charring-stability effect of phenylsiloxane group and the suppression effect of high-quality carbon layers were analyzed and summarized. It was expected that PVSi would pave the way for the development of more highly efficient flame retardant toughening agents and high-performance epoxy thermoset.

不良的冲击韧性和阻燃性能极大地限制了环氧热固性树脂的工程应用。为了获得高性能的环氧复合材料，合成了可再生的基于香兰素的阻燃增韧剂（PVSi），并将其掺入环氧树脂中。PVSi大分子的使用可以显着提高环氧树脂的冲击韧性。使用5 wt％的PVSi，环氧树脂的冲击强度最大提高了189.69％，从纯EP的12.42 kJ / m ²提高到EP / PVSi ₅复合材料的35.98 kJ / m ²。PVSi高分子对环氧树脂的增韧作用与其结构特征密切相关，例如柔性苯基硅氧烷，活性亚胺和极性磷菲基团。同时，EP / PVSi ₅复合材料在垂直燃烧测试（UL-94）中达到了V-0等级，在极限氧指数（LOI）中达到了29.5％，磷含量仅为0.27 wt％。另外，通过使PVSi大分子中的磷菲，苯基硅氧烷和二氨基二苯基砜基团共同发挥作用，可以获得抑制的热释放，明显减少的有毒的热解挥发物和增强的EP / PVSi复合材料的炭化能力。这些结果表明改善了环氧树脂的防火安全性。此外，P·和PO·的自由基清除作用，不燃NH ₃和SO ₂的燃料稀释作用分析并总结了焦磷酸和间磷酸的催化炭化效果，苯基硅氧烷基的炭化稳定性效果以及高质量碳层的抑制效果。预计PVSi将为开发更高效的阻燃增韧剂和高性能环氧热固性铺平道路。