BT-CNT复合颗粒填充聚偏二氟乙烯介电性能的研究

Dielectric Properties of PVDF Filled by BT-CNT Composite Particles

利用机械球磨法制备了钛酸钡表面负载碳纳米管的复合颗粒BT-CNT,将其填充到聚偏二氟乙烯中制备了三相复合材料(BT-CNT/PVDF),研究BT-CNT对该复合材料介电性能的影响。结果表明:随着BT-CNT质量分数的增加,复合材料的介电常数显著增加,而介质损耗及电导率仍保持在较低值,复合材料在BT-CNT质量分数为50%时未出现典型的渗流效应。介电常数的增加主要源于导电性CNT引起的界面极化,而长的CNT经机械球磨在BT表面形成较短的CNT片段,静电吸附于BT表面,难以在整个复合材料中形成导电性渗流网络。复合材料的介电常数随测试温度的升高而增大,这是由于温度升高导致更强烈的界面极化。

Composite particles （BT-CNT）, which was carbon nanotube（CNT） supported on the BaTiO3（BT）surface, were prepared through mechanical ball milling method, and a three-phase composite BT-CNT/PVDF was prepared by filling the BT-CNT into poly（vinylidene fluoride） （PVDF）. The effect of BT-CNTon the dielectric properties of the composites was studied. The results show that with the increase of themass fraction of BT-CNT, the dielectric constant of the composite increases obviously, and the dielectricloss and conductivity maintain at low value. No typical percolation effect is observed for the compositeseven when the mass fraction of BT-CNT reaches 50%. The increase of dielectric constant mainly derivesfrom the interfacial polarization caused by the electrical conductive CNT. The long CNT is broken intoshort CNT pieces after mechanical ball milling process and then is absorded to the BT surface throughelectrostatic attraction, thus it is hard to form conductive percolation network in the whole composite.The dielectric constant increases with the increase of temperature because high temperature would lead tostronger interfacial polarization.