氢氧化镁粒径对阻燃聚乙烯复合材料性能的影响

Effects of Magnesium Hydroxide with Varied Diameter on Properties of Flame Retardant Polyethylene Composites

以三种粒径的氢氧化镁(1.5、3.1以及6.4μm)为阻燃剂,氢氧化镁与低密度聚乙烯共混,制备聚乙烯/氢氧化镁阻燃复合材料。研究氢氧化镁的粒径对复合材料力学性能、电学性能、阻燃性能以及热稳定性的影响。结果表明:当氢氧化镁粒径增至6.4μm,复合材料的拉伸强度与断裂伸长率分别降至14.2 MPa和199.0%。随着氢氧化镁粒径的增加,复合材料的阻燃性能逐渐提高。当氢氧化镁粒径增至6.4μm,复合材料的最大热释放速率降至350 kW/m~2以下,氧指数(LOI)提高至22.8%。随着氢氧化镁粒径增加,复合材料的电学性能明显下降,介电损耗明显增加,体积电阻率由6.9×10^(13)Ω·m降至1.5×10^(13)Ω·m。综上分析,当氢氧化镁粒径为3.1μm,复合材料的综合性能最佳。

Polyethylene/magnesium hydroxide flame retardant composites were prepared by blending magnesium hydroxide with low density polyethylene using magnesium hydroxide with three particle sizes(1.5,3.1 and 6.4 μm) as flame retardant.The effects of particle size of magnesium hydroxide on mechanical properties,electrical properties,flame retardancy and thermal stability of the composites were studied.The results show that when the particle size of magnesium hydroxide increases to 6.4 μm,the tensile strength and elongation at break of the composites decrease to 14.2 MPa and 199.0%,respectively.With the increasing of magnesium hydroxide particle size,the flame retardant properties of the composites are gradually improved.When the particle size of magnesium hydroxide increases to 6.4 μm,the maximum heat release rate of the composite decreases to below 350 kW/m~2,and the oxygen index(LOI) increases to 22.8%.With the increasing of magnesium hydroxide particle size,the electrical properties of the composites decrease significantly,the dielectric loss increases significantly,and the volume resistivity decreases from 6.9×10^(13)Ω·m to 1.5×10^(13)Ω·m.In summary,when the particle size of magnesium hydroxide is 3.1 μm,the composite has the best comprehensive performance.