Wang Yaqiao, Jiang Hanchuan, Ni Jingyue, Chen Jianze, Zhou Hongfu, Wang Xiangdong, Xin Fei
School of Materials and Mechanical Engineering, Beijing Technology and Business University Beijing 100048 People's Republic of China
Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics Beijing 100048 People's Republic of China.
RSC Adv. 2018 Dec 21;9(1):192-205. doi: 10.1039/c8ra09680e. eCollection 2018 Dec 19.
A new class of brominated polymeric flame retardant (PolyFR) which is a kind of environmental FR was researched. Hydrotalcite (HT), applied as an environmentally-friendly heat stabilizer for PolyFR, was investigated by thermogravimetric analysis (TGA). It presented the result that no more than 0.15% HT significantly improved the thermal stability during processing but excessive HT would weaken the flame retardancy of PolyFR because of the ability to absorb hydrogen bromide (HBr). Flame-retardant polystyrene (PS) was prepared mixing PolyFR/BDDP/HT and then introducing inorganic particles such as antimonous oxide (SbO), organo montmorillonite (OMMT) and graphite to study their effect on the PolyFR/BDDP/HT system. The PS foams were prepared by batch foaming of the PS composites. Meanwhile, the combustion properties of PS composites and PS composite foams were characterized by limiting oxygen index (LOI) and vertical flame test (UL-94). The results indicated that the 2.5%PolyFR/2.5%BDDP/0.15%HT/PS composite possessed 25.7% LOI and pass UL-94 V-2 rating, while its foam possessed 30.7% LOI and pass UL-94 V-2 rating. And the addition of SbO, OMMT and graphite reduced the oxygen index and vertical burning performance of PS composites and PS composite foams to different degrees. Otherwise, the flame-retardant (FR) mechanism of each FR system was studied by TGA and cone calorimetry. This revealed that PolyFR/BDDP promoted decomposition and dripping of PS early to remove heat through droplets and released HBr to quench free radicals and dilute combustible gas and oxygen during combustion. These properties of PolyFR/BDDP helped reduce the burning intensity and extinguish the flame through droplets, thereby endowing PS and its foam with better fire-resistant properties. When the addition of SbO, OMMT or graphite improved the thermal stability of PS, they weakened the droplet effect as well. Besides, PS foams were characterized by scanning electron microscopy (SEM). The results indicated PolyFR played an efficient heterogeneous cell nucleation role in the foaming process to reduce average cell size (from 110.5 μm to 38.4 μm) and narrow cell distribution (from 60-160 μm to 20-60 μm).
研究了一类新型的溴化聚合物阻燃剂（PolyFR），它是一种环保型阻燃剂。采用热重分析（TGA）对用作PolyFR环保型热稳定剂的水滑石（HT）进行了研究。结果表明，不超过0.15%的HT能显著提高加工过程中的热稳定性，但过量的HT会因吸收溴化氢（HBr）的能力而削弱PolyFR的阻燃性。通过混合PolyFR/BDDP/HT，然后引入无机颗粒如氧化锑（SbO）、有机蒙脱土（OMMT）和石墨来制备阻燃聚苯乙烯（PS），以研究它们对PolyFR/BDDP/HT体系的影响。通过对PS复合材料进行间歇发泡制备PS泡沫。同时，通过极限氧指数（LOI）和垂直燃烧试验（UL-94）对PS复合材料和PS复合泡沫的燃烧性能进行了表征。结果表明，2.5%PolyFR/2.5%BDDP/0.15%HT/PS复合材料的极限氧指数为25.7%，通过UL-94 V-2等级，而其泡沫的极限氧指数为30.7%，通过UL-94 V-2等级。并且添加SbO、OMMT和石墨在不同程度上降低了PS复合材料和PS复合泡沫的氧指数和垂直燃烧性能。此外，通过TGA和锥形量热法研究了各阻燃体系的阻燃（FR）机理。结果表明，PolyFR/BDDP促进了PS的早期分解和滴落，通过液滴散热，并在燃烧过程中释放HBr以淬灭自由基、稀释可燃气体和氧气。PolyFR/BDDP的这些特性有助于降低燃烧强度并通过液滴熄灭火焰，从而赋予PS及其泡沫更好的耐火性能。当添加SbO、OMMT或石墨提高PS的热稳定性时，它们也削弱了液滴效应。此外，通过扫描电子显微镜（SEM）对PS泡沫进行了表征。结果表明，PolyFR在发泡过程中起到了有效的异质泡孔成核作用，从而减小了平均泡孔尺寸（从110.5μm减小到38.4μm）并使泡孔分布变窄（从60-160μm变为20-60μm）。
