磷酸三苯酯和甲基八溴醚在阻燃聚苯乙烯中的协同行为研究

Synergistic effect of triphenyl phosphate and methyloctabromoether on flame retardancy of polystyrene

为获得基于甲基八溴醚(MOBE)的高效阻燃聚苯乙烯(PS)复合体系,采用极限氧指数仪、锥形量热仪、热重分析仪(TG)和差示扫描量热仪(DSC)等对纯PS及其复合材料的阻燃性能及机理和热稳定性等进行了测试和表征,探索了MOBE与磷酸三苯酯(TPP)复配阻燃PS的行为规律。结果表明,TPP和MOBE复合体系比二者各自单独作为阻燃剂使用时赋予了PS材料更高的极限氧指数(LOI),PS/3%(质量分数,下同)TPP/4%MOBE的LOI可达27.7%,明显高于PS/4%MOBE(26.1%);3%TPP/4%MOBE能够在4%MOBE的基础上进一步抑制PS复合材料的燃烧强度,降低有效燃烧热,降低热释放速率峰值(PHRR)与总热释放量(THR);TPP和MOBE能够在PS复合材料热降解时将阻燃元素集中释放,同时发挥气相淬灭效应;此外,TPP的加入能够提高PS复合材料的熔体流动速率,降低其玻璃化转变温度,从而使PS热分解产生的熔滴更快地带走热量,最终使TPP与MOBE发挥更好的阻燃效果。

To obtain a high-efficient flame-retardant polystyrene(PS)composite system based on methyloctabromoether(MOBE),the flame-retardant properties and corresponding mechanisms of the flame-retardant PS compounds with MOBE and triphenyl phosphate(TPP)were investigated using a limiting oxygen index instrument,a cone calorimeter,a thermo-gravimetric analyzer,and a differential scanning calorimeter.The results indicated that the introduction of TPP and MOBE increased the limited oxygen index(LOI)of PS significantly compared to their use alone.The PS compound containing 3 wt%TPP and 4 wt%MOBE obtained an LOI of 27.7 vol%,which was 26.1%higher than the compound only containing 4 wt%MOBE.The burning intensity of this PS compound was further depressed,and its effective heat of combustion,peak heat release rate,and total heat release was reduced when compared to those of the compound only containing 4 wt%MOBE.TPP and MOBE could release the flame-retardant elements intensively during the thermal degradation process of PS compounds,exhibiting an efficient gas phase quenching effect.Moreover,the addition of TPP also improved the melt flow rate of PS compounds and reduced their glass transition temperatures.In this case,the generated droplets could take heat away faster from the PS thermal decomposition and finally make TPP and MOBE a better flame-retardant effect.