层状阻燃结构对PBT/IFR复合材料性能的影响

Influences of Layered Flame Retardant Structure on Properties of PBT/IFR Composites

通过熔融共混和模压成型技术制备了聚对苯二甲酸丁二酯(PBT)/膨胀型阻燃剂(IFR)共混和层状复合材料,其中层状复合材料为3层阻燃结构,内层为非阻燃层(纯PBT),内层外面两层为阻燃层(PBT/IFR)。通过UL94垂直燃烧、极限氧指数(LOI)以及拉伸和冲击性能测试对比分析了两种复合材料的阻燃性能和力学性能。结果表明,与PBT/IFR共混复合材料相比,PBT/IFR层状复合材料的阻燃性能提高幅度更大,虽然低IFR含量下其力学性能低于共混复合材料,但随着IFR含量增加,力学性能下降幅度更小。当层状复合材料中的阻燃层/非阻燃层/阻燃层的厚度比为1.5 mm/1 mm/1.5 mm,即IFR质量分数为22.5%时,其拉伸强度、断裂伸长率和冲击强度与相同IFR用量下的共混复合材料相当,而阻燃性能与IFR质量分数为30%的共混复合材料相当,其UL 94阻燃等级达到V–0级,LOI提高到24.4%。这表明,采用层状阻燃可控受限结构,可在较低的IFR用量下更好地提高PBT/IFR复合材料的阻燃性能,同时减缓了力学性能下降的幅度。

Blended and layered PBT/IFR composites were prepared by melting blending and compression molding technology.The layered PBT/IFR composites has three layers flame retardant structure,the middle layer is non flame retardant layer （purePBT）,two outer layers are flame retardant layers （PBT/IFR）. The flammability,mechanical properties of the two composites wereanalyzed by the UL 94 vertical combustion,limiting oxygen index （LOI）,tensile and impact properties test. The results show thatcompared with the blended composites,the flame retardancy of the layered composites is more promoted,and although the mechanicalproperties of the layered composites are lower than those of the blended composites at low IFR content,with increasing IFR content,the decline of the mechanical properties of the former is less. When the ratio of layer thickness of the flame retardant layer/nonflame retardant layer/flame retardant layer is 1.5 mm/1 mm/1.5 mm （ the mass fraction of IFR is 22.5%）,the tensile strength,elongation at break and impact strength of the layered composites are equal to the blended composites with the same content of IFR,the flame retardancy is equal to the blended composites with 30% IFR,the UL 94 flame retardant rating reaches V–0 and the LOIvalue increases to 24.4%. These suggest that using the controllable constrained layered flame retardant structure,the flame retardancyof PBT/IFR composite can be greatly promoted with less addition of IFR and the decline of mechanical properties are reduced.