电磁屏蔽材料的研究进展

介绍了电磁屏蔽材料在军用和民用领域的重要性;简要阐述了电磁屏蔽的机理;综述了4种不同电磁屏蔽材料的优缺点以及研究现状,分别为金属型、表面导电型、填充复合型和本征型导电聚合物电磁屏蔽材料;分析并提出了3种提高电磁屏蔽效能的方式,分别为多孔结构设计、多层结构设计、复合填料优化.     

电磁屏蔽材料的研究进展

介绍了电磁屏蔽材料在军用和民用领域的重要性;简要阐述了电磁屏蔽的机理;综述了4种不同电磁屏蔽材料的优缺点以及研究现状,分别为金属型、表面导电型、填充复合型和本征型导电聚合物电磁屏蔽材料;分析并提出了3种提高电磁屏蔽效能的方式,分别为多孔结构设计、多层结构设计、复合填料优化.     

三明治结构含铅聚酰亚胺材料的制备与辐射屏蔽性能研究

采用离子交换法合成了以化学方式键合铅离子的二胺单体4,4'-二氨基-1,1'-联二苯-2,2'-二磺酸铅BDSA(Pb),并与二胺单体4,4'-二氨基-二苯醚(ODA),二酐单体均苯四甲酸酐(PMDA)在溶剂N-甲基-2-吡咯烷酮(NMP)中完成缩聚反应,通过改变2种二胺单体的摩尔比,采用热亚胺法和流延法逐层浇筑的工艺,制备出了一系列侧基键合铅离子的三明治结构的聚酰亚胺复合材料PI(Pb),试图解决传统物理共混方法制备的复合材料中易出现的铅元素分布不均匀、机械性能差的科学问题.实验结果表明:以纯PI为参照物,制备的PI(Pb)复合材料对~(241)Am(59.5 keV)、~(238)Pu(79.9、176.7 keV)等中低能γ射线具有很好的屏蔽效果,而且具备优良的耐辐照性能、优异的热稳定性能和良好的力学性能.     

碳系填料填充聚合物基电磁屏蔽材料研究进展北大核心CSCD

电子电器设备的大量应用,使得电磁环境越来越复杂,对电磁屏蔽材料的需求也不断增长。与传统的金属填料相比,碳系填料具有品种多、质量轻、电导率高、来源广、耐腐蚀等独特优势,在聚合物基电磁屏蔽领域有着广阔的应用前景。本文主要介绍了炭黑、石墨、石墨烯、碳纳米管、碳纤维等碳系填料的结构与性能特点,并从填料形状,表面处理,复合技术等角度综述了近年来碳系填料填充改性制备聚合物基电磁屏蔽材料方面的研究进展。     

无纺布基聚吡咯柔性电极的储锂性能

高性能的柔性锂离子电池对可穿戴电子设备的发展具有重要意义。采用化学氧化法在聚对苯二甲酸乙二醇酯(PET)无纺布基材上原位聚合聚吡咯(PPy),并通过控制反应条件得到不同形貌的聚吡咯电极材料。当反应体系中剪切力较小时,得到纳米线状聚吡咯(PPy-NW/PET),反之,为纳米颗粒形貌的聚吡咯(PPy-NP/PET)。PPy纳米线的平均直径为460 nm,在包覆PET纤维的同时相互交叠,形成了三维网状导电通道。该PPy/PET可以直接作为无粘结剂的柔性电极材料。电化学测试结果表明,PPy-NW/PET电极材料的性能更优异,其首次放电和充电的比容量分别为124和98 mA[DK1]·h/g,且具有良好的柔性和稳定性。本文对柔性、轻质电极材料的制备及其在储能领域的应用提供了很好的思路。     

碳纳米管/聚合物基柔性电磁干扰屏蔽复合材料研究进展

当今,柔性可穿戴电子设备、航空航天等领域的快速发展对柔性、轻质电磁干扰(electromagnetic interference,EMI)屏蔽材料的需求不断增加,碳纳米管/聚合物基复合材料因具有柔性好、质量轻、导电性和机械稳定性优异、EMI屏蔽效能可调等优点而备受关注。本文介绍了电磁屏蔽机理,对碳纳米管的分散方法和碳纳米管/聚合物基柔性EMI屏蔽复合材料的制备方法进行了对比总结,综述了碳纳米管/聚合物基柔性EMI屏蔽复合材料的研究进展。最后,提出了碳纳米管/聚合物基柔性EMI屏蔽复合材料亟待解决的关键科学问题,并对其未来发展趋势进行了展望。     

共轭聚合物复合材料的结构和性能

对聚苯胺、聚吡啶等共轭聚合物与非导电聚合物材料的复合体系的结构和性能进行了综述。不同方法制备的复合材料在结构和性能上各有特点。一般共轭聚合物与非导电高分子材料相容性差、尤其是低极性高分了。     

BC/CoNi2S4@PPy柔性复合电极材料的制备及电化学性能

本文采用溶剂热、原位聚合和真空抽滤相结合的方法制备了用于超级电容器的细菌纤维素/镍钴硫化物/聚吡咯(BC/CoNi2S4@PPy)柔性电极材料,通过X 射线衍射、场发射扫描电镜、红外光谱、氮气吸脱附、拉伸强度和接触角表征了材料的形貌结构、组成、机械性能和亲水性,并采用循环伏安法和恒电流充放电测试了复合材料的电化学性能....     

矿物材料在电磁屏蔽中的应用研究

为解决电磁辐射污染问题,介绍了国内外矿物材料应用在电磁屏蔽方面的研究及最新进展,尤其是在建筑混凝土、涂料以及纳米矿物材料中的应用,归纳总结了其屏蔽特点和屏蔽效果,并对发展前景作出了展望.     

一种提高有机硅导电橡胶复合材料导电和电磁屏蔽性能的方法

描述了一种利用多元复合导电网络提高有机硅橡胶复合材料导电和电磁屏蔽性能的思想。这种含有多元复合导电网络的复合材料是通过将镀银泡沫、导电填料和有机硅橡胶复合在一起而制备的。利用扫描电子显微镜观察了复合材料的微观结构,采用电阻测试仪、矢量网络分析仪、热失重分析仪分别研究了复合材料的导电性、电磁屏蔽性能及热稳定性,并探讨了补强剂SiO2对这些性能的影响。结果表明,2%碳纳米管/导电泡沫/硅橡胶多元复合体系相比于2%碳纳米管/硅橡胶单一复合体系电阻率降低了6个数量级,平均电磁屏蔽效能由12dB提高到52dB,增大了4倍。当导电填料换为炭黑后,2%炭黑/导电泡沫/硅橡胶多元复合体系相比于2%炭黑/硅橡胶单一复合体系电阻率降低了7个数量级,平均电磁屏蔽效能由10dB提高到50dB,增大了5倍。由于多元复合导电网络,材料的导电性能和电磁屏蔽性能大幅度提升。此外,补强剂的加入增大了复合材料的热稳定性,但降低了其导电和电磁屏蔽性能。     

三明治结构多壁碳纳米管/聚醚醚酮电磁屏蔽复合材料的制备

以聚醚砜(PES)为黏结剂, 多壁碳纳米管(MWCNTs)为芯层, 聚醚醚酮(PEEK)薄膜为皮层, 制备了具有 三明治结构的MWCNTs/PEEK电磁屏蔽复合材料. 研究结果表明, 将适量的黏结剂PES引入到MWCNTs芯 层中, 当芯层层数增加到3层时, 复合材料的平均厚度仅有0.28 mm, 其密度、 拉伸强度、 5%热失重温 度(T_d,5%)、 导电率、 电磁屏蔽值及比电磁屏蔽值分别可以达到1.349 g/cm³, 80 MPa, 581.8 ℃, 2.6 S/cm, 32 dB及115 dB/mm, 是一种质量轻、 厚度薄、 机械性能好且电磁屏蔽性能高的复合材料. 其优异的综合性能主要归因于在三明治结构MWCNTs/PEEK复合材料的制备过程中, 在碳纳米管芯层中引入适量的聚醚砜作为黏结剂可以改善芯层内部碳纳米管之间及芯层与聚醚醚酮皮层之间的界面作用, 有利于芯层及芯层与皮层黏结成一个整体, 从而提高复合材料的机械性能; 同时, 芯层中碳纳米管互相搭接成密集导电网络又可以使得复合材料拥有较高的电磁屏蔽性能.     

屏蔽EMI的金属及炭素填充的高分子复合材料

屏蔽EMI材料是现代电子、电器工业不可缺少的材料之一,尤其是屏蔽EMI高分子材料已经成为绝大多数信息技术设备的壳体材料,它们在现代电子工业中有着举足轻重的地位.本文对屏蔽EMI的方法及高分子复合材料的特性和发展概况等作简要介绍.     

Electromagnetic Interference Shielding Polymers and Nanocomposites - A Review

Intrinsically conducting polymers (ICP) and conductive fillers incorporated conductive polymer-based composites (CPC) greatly facilitate the research in electromagnetic interference (EMI) shielding because they not only provide excellent EMI shielding but also have advantages of electromagnetic wave absorption rather than reflection. In this review, the latest developments in ICP and CPC based EMI shielding materials are highlighted. In particular, existing methods for adjusting the morphological structure, electric and magnetic properties of EMI shielding materials are discussed along with the future opportunities and challenges in developing ICP and CPC for EMI shielding applications.     

Progress in the Foaming of Polymer-based Electromagnetic Interference Shielding Composites by Supercritical CO2

As a critical action plan formulated for peaking carbon dioxide emissions, polymeric electromagnetic interference (EMI) shielding materials based on CO₂ foaming technology have recently been attracting widespread attention in both research and industry, attributable to their efficient use of CO₂, high specific strength, corrosion resistance and low-cost characteristics. In the past decade, the emergence of novel design concepts and preparation techniques for CO₂ foaming technology has led to the development of new high-performance EMI shielding materials in this field. This review summarizes the research progress made to date on the fabrication of EMI shielding composite foams by supercritical carbon dioxide (scCO₂) foaming. We also explore the structure-activity relationships between the component/distribution and EMI shielding properties. Additionally, the application prospects and development challenges of new EMI shielding composite foams are described.     

Electromagnetic interference shielding and radiation absorption in thin polypyrrole films

Results of permittivity measurements, electromagnetic interference shielding effectiveness, and heat generation due to microwave absorption in conducting polymer coated textiles are reported and discussed. The intrinsically conducting polymer, polypyrrole, doped with anthraquinone-2-sulfonic acid (AQSA) or para-toluene-2-sulfonic acid (pTSA) was applied on textile substrates and the resulting materials were investigated in the frequency range 1-18 GHz. The 0.54 mm thick conducting textile/polypyrrole composites absorbed up to 49.5% of the incident 30-35 W microwave radiation. A thermography station was used to monitor the temperature of these composites during the irradiation process, where absorption was confirmed via visible heat losses. Samples with lower conductivity showed larger temperature increases caused by microwave absorption compared to samples with higher conductivity. A sample with an average sheet resistivity of 150 Ω/sq. showed a maximum temperature increase of 5.27 °C, whilst a sample with a lower resistivity (105 Ω/sq.) rose by 3.85 °C.     

Biopolymer-Based Aerogels for Electromagnetic Wave Shielding and Absorbing

The rapid development of communication technology and electronic industry has brought unprecedented serious electromagnetic interference (EMI) and electromagnetic wave (EMW) pollution. Although EMI shields and EMW absorbers based on metal or magnetic materials were used to solve these problems, they have long been criticized for their high price, high density and easy corrosion. In order to achieve low density and efficient dissipation of electromagnetic energy, aerogels stand out among manifold materials. However, constructing aerogels with good EMI shielding or EMW absorption performance and acceptable mechanical properties is not an easy task. Burgeoning biopolymers, such as cellulose, lignin, chitin/chitosan and alginate, breathe new life into aerogels for high-efficiency EMW shielding and absorbing. Here, we reviewed the contributions of biopolymers in the fields of aerogels for EMW shielding and absorbing. At the same time, some challenges and outlook were also pointed out, aiming to promote the advance of aerogel-based EMI shields and EMW absorbers as well as the rational utilization of biopolymers.     

锡镍合金电磁屏蔽织物研制与镀层性能研究

在化学镀铜的涤纶织物上于焦磷酸盐体系电沉积均匀致密的锡镍合金层.改变镀液的NiSO4.6H2O、SnCl2.2H2O浓度比可获得不同锡含量、不同色泽的锡镍合金镀层.盐雾实验表明,含锡量为68.96%的电磁屏蔽织物表现出较好的耐蚀性和抗变色性.且其导电性优异,柔软、透气性好,具有柔和的外观,对人体无致敏性,在电磁兼容领域和民用市场有广阔的应用前景.     

柔性交联型聚酰亚胺气凝胶的制备及性能

利用溶胶-凝胶反应制备了聚酰亚胺凝胶, 经过超临界干燥得到了聚酰亚胺气凝胶. 研究了固含量和交联剂比例对气凝胶性能的影响规律. 结果表明, 聚酰亚胺气凝胶的密度和线收缩率都随着固含量和交联剂比例的增加而增加; 随着固含量的增加, 气凝胶的室温热导率呈现出先降低再增加的趋势(0.026~0.033 W·m^-1·K^-1), 气凝胶的力学刚度和强度明显提升; 交联剂的加入, 可以提高材料的韧性, 断裂应变最高达21.7%; 制得的柔性聚酰亚胺气凝胶具有良好的热稳定性, 是满足尖端武器以及空间飞行器对于轻质、 柔性热防护要求的理想材料之一.