多壁碳纳米管／聚偏氟乙烯高介电常数复合材料的制备与性能

Preparation and properties of multi-walled carbon nanotubes/poly(vinylidene fluoride)high dielectric constant composites

为制备具有高介电常数的复合材料,采用注射成型法制备了原始多壁碳纳米管(P-MWCNTs)/聚偏氟乙烯(PVDF)复合材料和石墨化多壁碳纳米管(G-MWCNTs)/PVDF复合材料。然后,对P-MWCNTs和G-MWCNTs进行了Raman光谱表征,对MWCNTs/PVDF复合材料进行了断面形貌、力学性能和电学性能测试。结果表明:G-MWCNTs比P-MWCNTs具有更高的纯度和结晶度,两种不同的MWCNTs都能均匀分散在PVDF基体中,添加MWCNTs会显著影响PVDF的力学行为。MWCNTs/PVDF复合材料的介电性能随MWCNTs含量的增加而提高,与P-MWCNTs相比,G-MWCNTs有效降低了复合材料的渗流阈值。当频率为100 Hz时,纯PVDF的介电常数为7.0;当P-MWCNTs的含量为5wt%时,复合材料的介电常数为23.8;当G-MWCNTs的含量为5wt%时,复合材料的介电常数高达105.0。注射成型法制备的MWCNTs/PVDF复合材料仍保持相对较低的电导率,进而导致复合材料的能量损耗较低,对电荷存储应用具有重要意义。

In order to prepare high dielectric constant composites, pristine multi-walled carbon nanotubes （P-MWCNTs）/poly （vinylidene fluoride） （PVDF） composites and graphitized multi walled carbon nanotubes （G-MWCNTs）/PVDF composites were prepared by injection molded method. Then G-MWCNTs and P MWCNTs were characterized by Raman spectroscopy, and the fracture morphologies, mechanical properites and electrical properties of MWCNTs/PVDF composites were measured. The results show that G-MWCNTs have higher purity and crystallinity than those of P-MWCNTs. Two kinds of different MWCNTs both disperse in the PVDF matrix uniformly. The addition of MWCNTs affects the mechanical behaviors of PVDF significantly. The dielectric proper- ties of MWCNTs/PVDF composites enhance with the content of MWCNTs increasing. Compared with P-MWC- NTs, G-MWCNTs reduce the percolation threshold of the composites effectively. When the frequency is 100 Hz, the dielectric constant of pure PVDF is 7.03 when the content of P-MWCNTs is 5wt~, the dielectric constant of composites is 23.8 ; when the content of G-MWCNTs is 5wt%, the dielectric constant of composites reachs up to 105.0. The MWCNTs/PVDF composites prepared by injection molded method remain relatively low conductivity, thus resulting in a lower energy loss and having great significances for the charge storage applications.