硅烷交联聚乙烯/氢氧化镁复合体系性能研究

Properties of the silane crosslinked polyethylene/Mg(OH)_2 composites

采用单螺杆挤出机作为反应器,以氢氧化镁(MH)为无卤阻燃剂,乙烯-醋酸乙烯酯共聚物为增容改性剂,制备出硅烷交联聚乙烯无卤阻燃材料。通过测试体系氧指数、拉伸强度、断裂伸长率以及采用SEM观察材料断面形貌,研究了交联度、氢氧化镁和EVA用量对复合体系阻燃性能、力学性能的影响,及EVA对硅烷交联/氢氧化镁(SXPE/MH)的微观结构的影响。结果表明,当凝胶质量分数为69%时,复合体系的氧指数为26.4,比未交联的增加了7.3%,拉伸强度达到24.3 MPa,提高了55.8%;当m(MH)∶m(PE)=140∶100时,SXPE体系的氧指数达到28.5,但其拉伸强度为19.1 MPa,下降了20%,断裂伸长率仅为130%,下降了51.8%;当m(EVA)∶m(PE)=10∶100时,复合体系氧指数为27.3,断裂伸长率增加到270%,达到最大值,比未添加EVA体系断裂伸长率增加了64.6%。

The silane crosslinked and flame retardant polyethylene was successfully obtained by single screw extruder,using magnesium hydroxide as holgens-free flame retardant and ethylene vinylacetate copolymer as compatibilizer.The flame retardant and mechanical property were investigated by oxygen index,tensile strength,breaking elongation and SEM.When content of gel reaches 69%,oxygen index of the compound system is increased by 7.6% compared with that without crosslink and tensile strength is improved 55.8%.The oxygen index of the SXPE system achieves 28.5 when m(MH)∶m(PE)=140∶100,and the tensile strength and elongation of which is decreased 20% and dropped 51.8% to 130% respectively.oxygen index of the compound system is 27.3 when m(EVA)∶m(PE)=10∶100,and elongation of which is increased 64.6% to 270% compared without EVA system.