反应性三源一体膨胀型阻燃剂阻燃聚丙烯的阻燃机理

Flame-Retardant Mechanism of Reactive Intumescent Flame Retardant in PP

利用自制的集"酸源、碳源、气源"于一体的反应性膨胀型阻燃剂EADP制备阻燃聚丙烯(PP),通过红外、锥形量热及扫描电镜法研究了EADP的阻燃机理。结果表明,阻燃PP燃烧时"三源"协同发生化学变化,迅速结炭和释放出NH3、H2O等不燃性气体,使阻燃PP形成内部多孔、表面致密的炭层,减少了挥发物中可燃气体的比例,突显出凝聚相和气相阻燃机理的作用。与原料PP相比,阻燃PP燃烧参数发生了很大变化,如加入质量分数25%EADP阻燃PP,峰值热释放速率(PHRR)、平均热释放速率(MHRR180)、平均有效燃烧热(av-EHC)、平均比消光面积(av-SEA)、火势增长指数(FIGRA)分别降低了65.50%、70.52%、19.51%、72.30%、82.25%,峰值热释放速率时间(TPHRR)是原料PP的1.9倍,呈现出优良的阻燃、抑烟效果。

Flame-retarded PP composites were prepared by blending PP with a reactive intumescent flame retardant(EADP) combining acid source,blowing agent and char-forming agent within an individual molecule. The flame-retardant mechanism of PP/EADP composites was investigated by Fourier transform infrared spectrum,cone calorimetry and SEM. The results show that during burning,three sources of EADP carry out a synergistical chemical reaction,forming char,releasing NH3,H2O and other non-flammable gases. The residual char of burned PP composites takes on a continuously compact surface and a cellular inner structure,which reduces the combustible gas to release. The result analysis reveals the coexistence of condensed-phase and gas-phase flame-retardant mechanisms. Compared with those of neat PP, the peak heat release rate(PHRR),mean heat release rate(MHRR180),average effective heat of combustion(avEHC),average specific extinction area(av-SEA),and fire growth index(FIGRA) of PP/EADP composite with 25% of EADP are decreased by 65. 50%,70. 52%,19. 51%,72. 3%,82. 3%,respectively. Simultaneously,the peak heat release rate time(TPHRR) is 1. 9 times longer than that of PP. Therefore,PP/EADP composites are endowed with excellent flame-retardant and smoke-suppression effect.