无机纳米ZnO或蒙脱土颗粒掺杂对低密度聚乙烯介电性能的影响

Effects of inorganic nano ZnO or montmorillonite inorganic nanoparticles on dielectric properties of low density polyethylene

选择在低密度聚乙烯(LDPE)中掺杂无机纳米ZnO和蒙脱土(MMT)颗粒,探讨不同形态无机纳米颗粒对LDPE介电性能的影响。利用熔融共混法配合不同冷却方式制备不同结晶形态的纳米ZnO/LDPE和MMT/LDPE复合材料。通过FTIR、偏光显微镜(PLM)、SEM、DSC和热刺激电流(TSC)对试样进行表征,并。研究了纳米ZnO/LDPE和MMT/LDPE复合材料的交流击穿特性,结果表明:掺杂适当质量分数并经表面修饰的无机纳米颗粒可有效的避免其团聚现象,提高纳米ZnO/LDPE和MMT/LDPE复合材料的结晶速率,使结晶结构更完善,同时无机纳米颗粒掺杂使LDPE的陷阱密度和深度均有所增加,载流子入陷在试样内部形成界面"局域态"。经油冷却方式制备的纳米ZnO/LDPE和MMT/LDPE复合材料击穿场强比空气自然冷却分别高13.6%和14.4%,当掺杂纳米粒子质量分数为3wt%时,复合材料击穿场强出现最大值,其中纳米ZnO/LDPE复合材料比MMT/LDPE复合材料的击穿场强值高0.68%;电导率试验结果表明:纳米ZnO/LDPE复合材料电导率比MMT/LDPE复合材料低。介电性能测试表明,在1～105 Hz的测试频率范围内,纳米ZnO/LDPE复合材料和MMT/LDPE复合材料介电常数降低,介质损耗角正切值有所提高。

The inorganic nano ZnO and montmorillonite（MMT）particles were doped in low density polyethylene（LDPE）.The effects of inorganic nano particles on the dielectric properties LDPE were discussed.The nano ZnO/LDPE and nano MMT/LDPE composites with different crystal habits were prepared using melt blending polymerization with different cooling methods.The samples were characterization using FTIR,polarizing microscopy（PLM）,SEM,DSC and thermally stimulated current（TSC）,and the alternating curren breakdown characteristics of nano ZnO/LDPE and nano MMT/LDPE composites was studied.The results indicate that doping proper mass fraction of the inorganic nanoparticles touched by the surface can avoid the agglomeration effectively.It can raise the crystallization rate and improve the crystalline texture of nano ZnO/LDPE and nano MMT/LDPE composites.The inorganicnano particles doping would increase the density and depth of LDPE.Inside the sample would form the interface＂localization state＂owing to the charge carrier is trapping.The breakdown field strength of nano ZnO/LDPE and MMT/LDPE composites prepared by oil cooling are 13.6%and 14.4% higher than that of the composites prepared by natural air cooling.When the content of the nano particles doped is 3 wt%,the breakdown strength of the composites appeares the highest values;the breakdown strength of ZnO/LDPE composite is 0.68% higher than that of MMT/LDPE composite.The conductivity experimental results show that the nano ZnO/LDPE composite conductivity is relatively lower than that of MMT/LDPE composite.The dielectric properties tests show that the nano ZnO/LDPE and MMT/LDPE composites dielectric constant decreases,and the tangent value of dielectric loss angle is improved in the range of 1-105 Hz test frequency.