含磷笼网结构多面体低聚倍半硅氧烷阻燃剂的合成及其阻燃环氧树脂性能

采用9，10-二氢-9-氧杂-10-膦菲-10-氧杂（DOPO）-乙烯基三甲氧基硅烷（VTMS）加成物DOPO-VTMS通过水解缩合反应，制备了新型含DOPO基团的笼网结构倍半硅氧烷（DOPO-PolyPOSS）。将不同比例的DOPO-PolyPOSS添加到环氧树脂（EP）中，制备了一系列阻燃EP。采用热重分析（TGA）、动态热机械分析（DMA）、万能拉力机、极限氧指数（LOI）、UL-94和锥形量热计对阻燃环氧树脂的热性能、力学性能和阻燃性能进行了系统研究，并通过热重-红外联用（TGA-IR）、热重-质谱联用（TGA-MS）和扫描电子显微镜（SEM）研究了其阻燃机理，结果表明：DOPO-PolyPOSS可在EP中均匀分散；向EP中加入DOPO-PolyPOSS显著提高了阻燃EP的残炭率，降低了热释放速率（HRR），延长了点燃时间（TTI），达到了良好的阻燃效果；当DOPO-PolyPOSS加入量（质量分数）为3%时，阻燃EP的LOI值可从纯EP的25.5%提高至31.7%，并达到了UL-94的V-0阻燃等级。此外，加入DOPO-PolyPOSS可提高EP的拉伸和弯曲性能。对EP凝聚相和气相裂解产物的分析结果表明，DOPO-PolyPOSS阻燃环氧树脂是基于磷硅协同效应而同时在气相和凝聚相阻燃。

Synthesis of cage-ladder-structure,phosphorus-containing polyhedral oligomeric silsesquinoxanes (POSS) and their performance as flame-retardants for epoxy resin

Novel cage-ladder structure phosphorus-containing polyhedral oligomeric silsesquinoxanes (DOPO-PolyPOSS) have been synthesized by hydrolytic condensation of 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-vinyltrimethoxysilane (DOPO-VTMS). The DOPO-PolyPOSS was incorporated into epoxy resins (EPs) in different ratios to form a series of flame retardant EPs. The effect of DOPO-PolyPOSS on the thermal, mechanical and flame retardant properties of EP was investigated. The experimental results showed that DOPO-PolyPOSS was homogeneously dispersed in the EP. The incorporation of DOPO-PolyPOSS enhanced char residue formation during thermal degradation of EP, reduced the heat release rate (HRR), and delayed the time to ignition (TTI) of EP in a fire. Interestingly, after the addition of only 3 wt% DOPO-PolyPOSS, the limiting oxygen index (LOI) value of the EP composite increased from 25.5% for pure EP to 31.7%, and vertical burning (UL-94) V-0 ratings were achieved. In addition, the EP composites showed improved tensile and flexural properties. Investigations of char residue and pyrolysis volatiles of cured EP further revealed that DOPO-PolyPOSS exerted simultaneous flame-retardant effects in both condensed and gas phases due to the synergistic effects between silicon and phosphorus.