Abstract A novel method was developed for the sampling of volatiles produced by polymer decomposition during UL-94 standard flammability tests, allowing collecting, separating and analyzing the precise composition of the fuel mixture feeding the flame in the real flaming conditions. The system was validated on epoxy resin/Polyhedral Oligomeric SilSesquioxanes (POSS) and found extremely informative for the understanding of the flame retardancy mechanisms previously referred to as the “blowing-out effect”. Collected products were analyzed by infrared spectroscopy and gas chromatography/mass spectroscopy, to identify the gaseous and liquid decomposition products, allowing depicting a comprehensive decomposition pathway for the epoxy resin. Lightweight volatiles, gaseous at room temperature, showed limited differences as a function of DOPO-POSS (polyhedral oligomeric silsesquioxane functionalized with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), whereas mixtures of liquid products evidenced for dramatic changes in the relative concentration as a function of DOPO-POSS. In pristine epoxy resin, the most abundant products were recognized as benzene, phenol, naphthalene and toluene, along with several tens of other aromatic products observed in lower amounts. The presence of DOPO-POSS at low concentration (2.5%) radically changes the composition of the aromatic volatiles mixture, as no significant amount of benzene is produced, while phenol becomes the main product, accounting for about half of the total, isopropyl phenol and bisphenol A, along with several tens of other products in lower concentrations. Such modification of the fuel mixture feeding the flame provided an explanation for the lower flammability of this formulation, as well as for the phenomenology of the blowing out effect.

中文翻译：

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在 UL 94 标准可燃性测试中对燃烧的环氧树脂分解产物进行 FTIR 和 GCMS 分析。应用于理解环氧树脂/多面体倍半硅氧烷配方中的吹出效应

摘要 开发了一种在 UL-94 标准可燃性测试中对聚合物分解产生的挥发物进行采样的新方法，可以收集、分离和分析在真实燃烧条件下供给火焰的燃料混合物的精确成分。该系统在环氧树脂/多面体低聚倍半硅氧烷 (POSS) 上进行了验证，发现对于理解以前称为“吹出效应”的阻燃机制非常有用。通过红外光谱和气相色谱/质谱分析收集的产物，以识别气态和液态分解产物，从而描绘环氧树脂的综合分解途径。轻质挥发物，室温下为气态，显示出作为 DOPO-POSS（用 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide 官能化的多面体低聚倍半硅氧烷）的函数的有限差异，而液体产品的混合物证明相对浓度的显着变化作为DOPO-POSS 的功能。在原始环氧树脂中，最丰富的产物被认为是苯、苯酚、萘和甲苯，以及少量观察到的几十种其他芳香族产物。低浓度 (2.5%) DOPO-POSS 的存在从根本上改变了芳香族挥发物混合物的组成，因为没有产生大量苯，而苯酚成为主要产物，约占总量的一半，异丙基苯酚和双酚 A，以及几十种其他浓度较低的产品。