新型功能石墨烯及其高介电常数低介电损耗环氧树脂基复合材料的研究

发布时间：2018-06-13 12:08

本文选题：石墨烯 + 复合材料　；参考：《苏州大学》2015年硕士论文

【摘要】：高介电常数(High-k)聚合物基复合材料作为电子、能量转换及存储材料等在众多尖端领域具有巨大的应用前景,受到研究者的广泛和高度关注。基于渗流理论的导体/聚合物基复合材料是制备High-k材料的重要类型。依据渗流理论,在渗流阈值(fc)附近发生介电常数的急增,但是同时也往往出现高介电损耗。如何降低导体/聚合物复合材料的介电损耗成为High-k材料研究的关键。大量研究证明,在导体的表面包覆绝缘层可以有效降低介电损耗,但是因阻碍了导电网络的形成而往往需要添加高含量的导体才能获得高介电常数。这不仅增加了复合材料的fc,而且劣化了复合材料的工艺性,甚至力学性能等其他性能。因此,研发一种兼具高介电常数、低介电损耗和低fc的树脂基复合材料具有重大意义。本文围绕这个目标而展开研究。从新型功能石墨烯的设计制备出发,以结构-性能为主线展开相关的研究。首先,我们制备了具有微电容结构的新型功能体(Ti O2@Ti B2-r GO),通过化学法在石墨烯(r GO)表面接枝具有核-壳杂化的功能体(Ti O2@Ti B2);而后在此基础上以环氧树脂(EP)为基体制备了系列Ti O2@Ti B2-0.75r GO/EP复合材料。探讨了不同含量Ti O2@Ti B2包覆的r GO对Ti O2@Ti B2-0.75r GO/EP复合材料的电学和介电性能的影响。研究结果表明,Ti O2@Ti B2-0.75r GO/EP复合材料不仅具有低fc(0.758wt%),而且具有高介电常数和低介电损耗。当Ti O2@Ti B2与r GO的质量比为0.1:1时,相应的3Ti O2@Ti B2-0.75r GO/EP复合材料在100Hz下的介电常数和介电损耗分别为77和0.55,各为相同r GO含量的0.75r GO/EP复合材料相应值的1.14和5.8×10-2倍。Ti O2@Ti B2-0.75r GO/EP复合材料具有高介电常数是因为复合材料中具有大量的微电容结构,其中导体Ti B2和r GO充当电极,而绝缘Ti O2充当介质。随着微电容结构的Ti O2@Ti B2-r GO功能体在EP中含量的增多,复合材料中会形成更多的微电容,从而有利于介电常数的提高。而低介电损耗的获得则是因为Ti O2@Ti B2隔绝了r GO的接触,切断了漏导电流,从而减少了电导损耗。此外,对Ti O2@Ti B2-r GO/EP复合材料的阻抗谱进行了电路模拟,深入探讨了具有微电容结构的Ti O2@Ti B2-r GO功能体对其复合材料介电性能的影响。其次,为了保持r GO优异的电学性能不遭到破坏,使得复合材料获得更高的介电常数,我们通过静电和π-π共轭双重作用将聚苯胺(r PANI)包覆的碳纳米管(CNT)负载于石墨烯(r GO)上,得到了具有“三明治”结构的官能化新型杂化导体(r PANI@CNT-r GO)。在此基础上,固定r GO含量为EP质量的0.75wt%,将具有不同r PANI包覆CNT(r PANI@CNT)负载量的r PANI@CNT-r GO与EP复合,制备了系列r PANI@CNT-0.75r GO/EP复合材料。与此同时,作为比较,以r PANI@CNT和r GO为导体,通过物理共混方法制备了r PANI@CNT/0.75r GO/EP复合材料,并系统研究了r PANI@CNT/0.75r GO/EP和r PANI@CNT-0.75r GO/EP复合材料的电学与介电性能。研究结果表明,r PANI@CNT/0.75r GO/EP复合材料均具有较低的介电常数(10-20),而r PANI@CNT-0.75r GO/EP复合材料的介电常数随着r PANI@CNT负载量的增加而升高。当负载量达到0.75wt%时,所制得的7r PANI@CNT-0.75r GO/EP复合材料的介电常数达210(100Hz),远高于r PANI@CNT/EP、0.75r GO/EP复合材料及r PANI@CNT/0.75r GO/EP复合材料的相应值。与此同时,7r PANI@CNT-0.75r GO/EP复合材料的介电损耗(100Hz)分别是后者的208、0.18和22倍,证明了r PANI@CNT-0.75r GO/EP复合材料的介电性能不是基本组成的简单加和,而是表现出显著的协同效应。此外,r PANI@CNT-0.75r GO/EP复合材料的渗流阈值仅为1.1wt%。
[Abstract]:High dielectric constant (High-k) polymer matrix composites, as electrons, energy conversion and storage materials, have great potential applications in many frontiers and are widely and highly concerned. Conductor / polymer matrix composites based on percolation theory are important types of preparation of High-k materials. There is a rapid increase in dielectric constant near the value (FC), but high dielectric loss is often found at the same time. How to reduce the dielectric loss of conductor / polymer composites is the key to the research of High-k materials. A large number of studies have shown that dielectric loss can be effectively reduced on the surface of the conductor, but the formation of a conductive network is hindered. It is often necessary to add a high content of conductors to obtain high dielectric constant. This not only increases the FC of the composite, but also deteriorates the technological properties of the composites, even the mechanical properties. Therefore, it is of great significance to develop a resin based composite with high dielectric constant, low dielectric loss and low FC. The research. Starting from the design of the new functional graphene, the related research was carried out with the structure and properties as the main line. First, we prepared a new functional body (Ti O2@Ti B2-r GO) with micro capacitance structure (B2-r GO), which was chemically bonded to Shi Moxi (R GO) on the surface of the R GO (Ti O2@Ti B2); and then, A series of Ti O2@Ti B2-0.75r GO/EP composites were prepared on the basis of epoxy resin (EP). The effect of R GO coated on Ti O2@Ti B2 on the electrical and dielectric properties of Ti O2@Ti composites was investigated. High dielectric constant and low dielectric loss. When the mass ratio of Ti O2@Ti B2 and R GO is 0.1:1, the dielectric constant and dielectric loss of the corresponding 3Ti O2@Ti B2-0.75r GO/EP composites are 77 and 0.55 respectively under 100Hz, each of which is 1.14 and 5.8 x 10-2 times the corresponding value of the same R. The high dielectric constant is because there are a large number of micro capacitance structures in the composite, in which the conductors Ti B2 and R GO act as electrodes, and the insulating Ti O2 acts as the medium. With the increase of the Ti O2@Ti B2-r GO function in the micro capacitance structure, more micro capacitance will be formed in the composite material, which is beneficial to the improvement of the dielectric constant. The dielectric loss was obtained because Ti O2@Ti B2 isolated the contact of R GO, cut off the leakage current and reduced the conductance loss. In addition, the impedance spectrum of Ti O2@Ti B2-r GO/EP composite material was simulated and the effect of Ti O2@Ti B2-r function on the dielectric properties of the Ti O2@Ti B2-r GO/EP composite was deeply discussed. In order to keep the excellent electrical properties of R GO without damage and make the composite obtain higher dielectric constant, we load the carbon nanotube (CNT) coated with polyaniline (R PANI) on the graphene (R GO) by electrostatic and PI - conjugation, and obtain a new functionalized hybrid conductor with a "sandwich" structure (R PANI@CNT-). R GO). On this basis, the EP mass of 0.75wt% with the content of R GO is fixed. The electrical and dielectric properties of R PANI@CNT/0.75r GO/EP and R PANI@CNT-0.75r GO/EP composites are systematically studied by /EP composites. The results show that R PANI@CNT/0.75r GO/EP composites have low dielectric constant (10-20), while the dielectric constant of R PANI@CNT-0.75r composites increases with the increase of load. When the load is up to 0.75wt%, the dielectric constant of the 7R PANI@CNT-0.75r GO/EP composite is 210 (100Hz), which is much higher than that of R PANI@CNT/EP, 0.75r GO/EP composite and R PANI@CNT/0.75r GO/EP composites. At 0.18 and 22 times, it is proved that the dielectric properties of R PANI@CNT-0.75r GO/EP composites are not a simple addition to the basic composition, but a significant synergistic effect. In addition, the percolation threshold of the R PANI@CNT-0.75r GO/EP composite is only 1.1wt%.
【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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