柔性碳纳米管宏观膜的无损分离及其电沉积铜的电磁屏蔽性能

发布时间：2018-05-01 20:07

本文选题：碳纳米管宏观膜 + 分离　；参考：《江西理工大学》2017年硕士论文

【摘要】：随着电子科学与信息技术的高速发展,电子设备及器件正大规模地普及。这些电子设备产生的电磁波为人类生活带来极大便利的同时也带来了一定的安全隐患。因而须使用电磁屏蔽材料屏蔽电磁波产生的辐射。目前常用的屏蔽材料主要为金属材料和导电填充型复合材料等。但是这类材料密度高、不具有柔性,因而给较多场合的使用带来了不便。碳纳米管(CNTs)作为一种新型纳米材料,表现出了优异的屏蔽性能。通常CNTs作为导电填充剂添加到高分子聚合物上,用于制备电磁屏蔽材料。但是该法制备的屏蔽材料由于其填充量有限导致屏蔽效能不高、质量不够轻。本研究以CNTs宏观膜(CMF)作为基体制备电磁屏蔽材料。在制备CMF时,通常需要基底作支撑,要实现CMF的应用需要将其从基底上分离成自支撑CMF。按目前方法,实现CMF从基底上分离成自支撑膜尚有一定难度。本文对制备的CMF做了一些无损分离的尝试,并研究了其电磁屏蔽性能。(1)本文采用浮动催化裂解的化学气相沉积法(CVD)合成了CNTs,并通过乙醇水溶液(Vol%,50%)将其置于打印纸上组装并分离了CMF。探讨了CMF与打印纸间的组装和分离机理。在乙醇水溶液的作用下,CNTs吸附在打印纸上组装成CMF,它们间仅发生物理吸附而不发生化学吸附。在微观尺度下,打印纸表面具有较大的表面平均粗糙度,使得CMF易从打印纸上分离。(2)通过XRD、SEM、HR-TEM等手段表征CMF的结构和形貌。在宏观尺度上,CMF具有平整的表面、良好的厚度均匀性,同时还具有良好的石墨化结构。经过10%以下的拉伸变形,其导电性变化很小,表明经过弯曲、折叠等操作不会影响CMF的使用。制备的CMF尺寸高达1880 mm*1000 mm。(3)通过电沉积的方式在CMF表面沉积Cu薄层,得到了Cu/CMF复合材料,并对其柔性、屏蔽性能进行研究。发现Cu/CMF具有与Cu箔一致的导电性,经多次折叠甚至揉搓后,依旧保持了其质轻、高柔的特点。在高频波段,Cu/CMF比CMF和填充Fe纳米颗粒的CMF具有更高的屏蔽效能。相比电沉积Cu前的CMF,在10-18 GHz频率范围内,其平均屏蔽效能提高了10.3-25.7%,最高达55%。与填充Fe纳米颗粒的CMF相比,在9-18 GHz频率范围内,其平均电磁屏蔽效能提高了7.5-19%。在~15 GHz时,Cu/CMF的电磁屏蔽效能高达53.3 dB。
[Abstract]:With the rapid development of electronic science and information technology, electronic devices and devices are popularizing on a large scale. The electromagnetic wave generated by these electronic devices brings great convenience to human life, but also brings some security risks. Therefore, electromagnetic shielding materials must be used to shield the radiation generated by electromagnetic waves. At present, the main shielding materials are metal materials and conductive filled composites. However, this kind of material is not flexible because of its high density, so it is inconvenient to be used in many occasions. Carbon nanotubes (CNTs), as a new nano material, exhibit excellent shielding properties. CNTs is usually added to polymer as a conductive filler to prepare electromagnetic shielding materials. However, the shielding material prepared by this method is of low shielding efficiency and low mass due to its limited filling. In this study, electromagnetic shielding materials were prepared by using CNTs macroscopical membrane as substrate. In the preparation of CMF, the substrate is usually needed as the support, and to realize the application of CMF, it is necessary to separate it from the substrate into self-supporting CMF. According to the present method, it is difficult to separate CMF from the substrate into self-supporting membrane. In this paper, we try to separate the CMF without damage. In this paper, CNTswere synthesized by floating catalytic pyrolysis chemical vapor deposition (CVD). The CNTswere assembled and separated on printed paper by ethanol aqueous solution. The mechanism of assembly and separation between CMF and printing paper was discussed. CNTs were adsorbed on printed paper to form CMFs under the action of ethanol aqueous solution, and there was only physical adsorption and no chemisorption between them. On the micro scale, the surface of printing paper has a large average surface roughness, which makes it easy for CMF to be separated from printing paper.) the structure and morphology of CMF are characterized by means of XRDX, SEM, HR-TEM and so on. The CMF has a smooth surface, a good thickness uniformity and a good graphitization structure. After tensile deformation of less than 10%, the electrical conductivity change is very small, indicating that after bending, folding and other operations will not affect the use of CMF. The size of the prepared CMF is up to 1880 mm*1000 / mm 路m3) Cu thin layer was deposited on the surface of CMF by electrodeposition, and its flexibility and shielding properties were studied. It is found that Cu/CMF has the same electrical conductivity as Cu foil. After fold and even knead for many times, Cu/CMF still keeps its characteristics of light weight and high flexibility. The shielding efficiency of Cu / CMF in high frequency band is higher than that of CMF and CMF filled with Fe nanoparticles. Compared with the CMF before electrodeposition, the average shielding efficiency increased by 10.3-25.7in the frequency range of 10-18 GHz. Compared with the CMF filled with Fe nanoparticles, the average electromagnetic shielding efficiency increases 7.5-19 in the range of 9-18 GHz frequency. At 15 GHz, the electromagnetic shielding efficiency of Cu- / CMF is as high as 53.3 dB.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB34

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