六苯氧基环三磷腈与四溴双酚A对聚丙烯的协同阻燃作用

摘要

通过极限氧指数测定(LOI)、垂直燃烧实验和锥型量热仪分析研究了六苯氧基环三磷腈(HPTCP)与四溴双酚A (TBA)对聚丙烯(PP)的协同阻燃作用.结果表明,在阻燃剂添加量为12.5％时,TBA阻燃PP和HPTCP阻燃PP的LOI分别为25.0％和20.8％,垂直燃烧均无阻燃等级,而二者以质量比1∶1复合阻燃PP的LOI为28.2％,阻燃等级达到FV-2级,且后者的点燃时间较前两者长,热释放速率、质量损失率和累计热释放量均比前两者小,这说明两者之间具有很好的协同作用.热重分析和残炭分析结果表明,TBA/HPTCP是通过气相和凝聚相协同阻燃的,即TBA/HPTCP一方面协同加速PP的炭化,减少可燃挥发物的产生,另一方面TBA分解释放出的HBr捕获燃烧产生的自由基而抑制气相燃烧.%Synergistic flame retardancy of phenoxycycloposphazene ( HPTCP) and tetrabromobisphenol A (TBA) in polypropylene was studied by limiting oxygen index ( LOI) measurement, vertical burning and cone calorimeter test (CCT). When the loading of the flame retardant was 12. 5 wt% , the LOI of the flame retarded PP ( TOP and HPP) with only TBA or HPTCP were respectively 25.0 and 20.8, and had no vertical flammability rating, while the LOI of the sample ( THP) with a combination of TBA and the same weight amount of HPTCP can be up to 28. 2% , vertical flammability class meet FV-2. The ignition time of THP was longer than of TBP and HPP, while the heat release rate, mass loss rate and total heat release of THP was smaller than those of TBP and HPP. The above results revealed that the synergistic flame retardancy of HPTCP and TBA in polypropylene was excellent. TGA and carbon residue analysis indicated that TBA/ HPTCP played a flame retardancy by gas and condensed phase mechanisms, where on the one hand, TBA/ HPTCP accelerated synergic the carbonization of PP, on the other hand, the HBr released from the decomposition of TBA inhibited combustion by capturing radicals generated from combustion.