【作者】 武晋萍；

【导师】 党智敏；

【作者基本信息】 北京化工大学 ， 材料学， 2008， 硕士

【摘要】 随着电子和信息领域的迅速发展,对介电材料的性能提出了更高的要求。单一材料性能难以满足其要求,故复合两种或两种以上的材料利用各自的优势制备具有高介电常数和良好加工性能的材料成为该领域研究的热点。碳纤维具有很好的力学性能,较高的电导率和较大的长径比,在功能型复合材料领域有着广泛的应用。根据渗流理论,高电导率和大长径的填料同时也是高介电复合材料的理想填料。所以研究短切碳纤维/聚合物复合材料的介电性能有着重要的意义。本文主要研究了采用溶液法制备的填充不同种类和不同含量填料的碳纤维/聚偏氟乙烯(CF/PVDF)复合材料的介电性能。结果表明,利用短切碳纤维作为填料可制备出渗流阈值仅为0.066,介电常数为85的高介电、低渗流阈值的复合材料。为了增强碳纤维语聚合物的结合力,采用硝酸对碳纤维表面进行了氧化处理。结果表明,表面酸处理能够增加碳纤维表面的活性含氧基团和粗糙度,从而增加了碳纤维与聚偏氟乙烯基体的相容性。酸处理的碳纤维填充的复合材料介电常数在低频下(1000Hz)高达315左右,相比于未处理的碳纤维填充复合材料而言,具有较高的渗流阈值。也探讨了利用三氟甲基苯胺对碳纤维化学修饰的结果。更多还原

【Abstract】 With the rapid development of electronic and informational industries, it puts forward more requirements for the properties of dielectric materials. Because one kind of material can not reach these requirements, integrating two or more materials with complementary properties and preparing composite with high dielectric constant and easy processing properties has been the key point of the research among the researchers in this field. Carbon fiber (CF) with excellent mechanical property, large aspect ratio and high electrical conductivity has been broadly used to prepare the composites with excellent mechanical properties. According to the percolation theory, fillers with high electric conductivity and large aspect ratio are quite suitable for preparing the composites with high dielectric constant. Therefore, it is very significant to investigate the dielectric property of CF/polyvinylidene fluoride (PVDF) composite.In this work, the dielectric properties of CF/PVDF composites prepared by solution methods which were filled with different kinds and volume fraction of CF were mainly studied. The results show that the CF/PVDF composites with dielectric constant of 85 and low percolation threshold of 0.066 was obtained. Surfaces of the CF were modified by nitric acid and p-(trifluromethy)laniline. The results show that the compatibility has been enhanced by increasing the oxygen groups and coarseness on the surface of CF. At the low frequency (1000 Hz), the dielectric constant of composite filled with acid treated CF is as high as 315 proximately. The percolation threshold of the composite filled with acid treated CF is higher than that of composites with untreated carbon fibers. The chemical modifications on the surface of the CF using p-(trifluromethy) laniline were also investigated in this work.更多还原