Phosphoric triamide (PTA) and glycidyl polyhedral oligomeric silsesquioxane (POSS) were simultaneously incorporated into the cured network of a bisphenol F epoxy resin and 4,4′-diaminodiphenyl methane (DDM) to improve the thermal stability and flame retardancy. PTA was synthesized by triethyl phosphate and DDM, and its chemical structure was confirmed by 1H nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR). The differential scanning calorimetric (DSC) results showed that the introduction of PTA and POSS slightly increased the glass transition temperature of the epoxy resin. The thermogravimetric analysis results indicated that compared with the pure, phosphoric, and silicic epoxy resins, the modified epoxy resin possessed the lowest weight loss rate and highest char residue. Its limiting oxygen index value was as high as 30.5, and the UL-94 grade reached V-1. A decomposition test was carried out to obtain sufficient char residue and investigate the condensed mechanism. The scanning electron microscopic images demonstrated that the char residue of the modified epoxy resin had a compact structure. The energy dispersive X-ray and FTIR analyses verified the synergistic effect of the phosphorus and silicon in the PTA and POSS, respectively, on the epoxy resin.

中文翻译：

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磷酸三酰胺和缩水甘油基POSS改性环氧树脂的热稳定性和阻燃性

将磷酸三酰胺 (PTA) 和缩水甘油多面体低聚倍半硅氧烷 (POSS) 同时掺入双酚 F 环氧树脂和 4,4'-二氨基二苯甲烷 (DDM) 的固化网络中，以提高热稳定性和阻燃性。PTA由磷酸三乙酯和DDM合成，其化学结构经1H核磁共振(NMR)和傅里叶变换红外(FTIR)确证。差示扫描量热（DSC）结果表明，PTA和POSS的引入略微提高了环氧树脂的玻璃化转变温度。热重分析结果表明，与纯环氧树脂、磷酸环氧树脂和硅环氧树脂相比，改性环氧树脂的失重率最低，残炭率最高。其极限氧指数值高达30.5，UL-94等级达到V-1。进行分解试验以获得足够的焦炭残留物并研究凝聚机理。扫描电镜图像表明改性环氧树脂的炭渣结构致密。能量色散 X 射线和 FTIR 分析分别验证了 PTA 和 POSS 中的磷和硅对环氧树脂的协同作用。