At present, designing efficient bio-based flame retardants for epoxy resin (EP) and exploring low-toxicity and sustainable flame retardant strategies is still a great challenge. In this work, a novel bio-based hybrid flame retardant was successfully prepared by constructing a resveratrol-based cyclic cross-linked polyphosphazene (PPZ) shell on the surface of halloysite nanotube (HNT). The enhancement effects of HNT@PPZ on the fire safety of EP composites were investigated by thermal degradation, simulated fire performance (cone calorimeter test), gas-phase product analysis, and condensed-phase char residue analysis. Compared to pure EP, he total heat release (THR), total smoke production (TSP) and the average yield of carbon monoxide (Av-COY) of EP/3HNT@PPZ were reduced by 47.8 %, 46.5 % and 48.8 % respectively. Furthermore, the EP composites containing HNT@PPZ had a stable flame retardancy even after 6 months of natural aging. It was found the barrier effect of HNT@PPZ in condensed phase was further strengthened by the formation of new product aluminum phosphate, which formed a multiple protective char layer. Additionally, PPZ shell improved compatibility and dispersion of HNT in EP matrix, the mechanical properties of the composite with HNT@PPZ were improved significantly. This work proposed a feasible solution for the preparation of highly efficient bio-based flame retardants with excellent heat reduction and smoke toxicity reduction ability, which could be expected to broaden the application of biomass resources in the development of highly efficient flame retardants.

中文翻译：

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生物源聚磷腈改性埃洛石纳米管作为环保阻燃剂可显着减少烟雾释放并提高环氧树脂的防火安全性

目前，设计用于环氧树脂（EP）的高效生物基阻燃剂并探索低毒和可持续的阻燃策略仍然是一个巨大的挑战。本工作通过在埃洛石纳米管（HNT）表面构建白藜芦醇基环状交联聚磷腈（PPZ）壳层，成功制备出一种新型生物基杂化阻燃剂。通过热降解、模拟燃烧性能（锥形量热仪测试）、气相产物分析和凝相残炭分析研究了HNT@PPZ对EP复合材料防火安全性的增强效果。与纯EP相比，EP/3HNT@PPZ的总放热量（THR）、总发烟量（TSP）和平均一氧化碳产率（Av-COY）分别降低了47.8%、46.5%和48.8%。此外，含有HNT@PPZ的EP复合材料即使在自然老化6个月后仍具有稳定的阻燃性能。研究发现，凝相态HNT@PPZ的阻隔作用通过新产品磷酸铝的形成进一步增强，从而形成多重保护炭层。此外，PPZ壳改善了HNT在EP基体中的相容性和分散性，HNT@PPZ复合材料的力学性能显着提高。该工作为制备具有优异的减热和烟毒减毒能力的高效生物基阻燃剂提出了可行的解决方案，有望拓宽生物质资源在高效阻燃剂开发中的应用。