Structural effects in a composite nonwoven fabric on EMI shielding
Structural effects in a composite nonwoven fabric on EMI shielding
复制标题
复合非织造布的结构对 EMI 屏蔽的影响
DOI：
10.1016/j.matdes.2017.02.025
复制
发表时间：
2017-04-15
影响因子：
8.4
通讯作者：
Tang, Yong
中科院分区：
文献类型：
--
作者：
Lu, Longsheng;Xing, Di;Tang, Yong
采用碳纤维（CF）和聚丙烯/聚乙烯（PP/PE）芯/皮型双组分纤维（ESFs）制备了CEF-NF复合非织造布。由于其良好的机械强度、优异的柔韧性、超薄的厚度和卓越的电气性能，它作为电磁干扰（EMI）屏蔽材料具有很大的前景。本文介绍了一种复合CEF-NF制造通过两步湿造纸/热粘合工艺。建立了一套法兰同轴测试系统，在30 ~ 1500 MHz频率范围内研究了材料结构对CEF-NF织物电磁屏蔽效能（EMI-SE）的影响。结果表明，CEF-NF的结构与其EMI SE性能高度相关，其随着面密度、纤维长度和CF浓度的增加而增加。在一组优化的工艺参数下，仅用40wt%的CF和50 g/m2的面密度，CEF-NF的EMI-SE就可以达到高达30.29dB或110www.example.com（3）/g的特定总EMI-SE-满足商业EMI要求。dB.cm最后，对理想和实际的电磁屏蔽机理进行了全面的研究和分析。研究发现，CEF-NF的电渗流阈值对实际的吸收和反射性能有很大的影响。在电导率阈值下，CEF-NF表现出较高的吸收性能。(C)2017爱思唯尔有限公司版权所有
A composite nonwoven fabric named CEF-NF in previous work was fabricated with carbon fibers (CFs) and poly-propylene/polyethylene (PP/PE) core/sheath bicomponent fibers (denoted as ESFs). It holds great promise as an electromagnetic interference (EMI) shielding material, due to its good mechanical strength, excellent flexibility, ultra-thin thickness and remarkable electrical properties. This paper demonstrates a composite CEF-NF fabricated via two-step wet-papermaking/thermal-bonding processes. A flange coaxial test system was established to investigate the influences of material structure on EMI shielding effectiveness (EMI-SE) of CEF-NF fabrics in 30- 1500 MHz frequency range. Results indicate that the structure of a CEF-NF is highly correlated to its EMI SE property, which increases with increasing areal density, fiber length and CF concentration. Under a set of optimal process parameters, the EMI-SE of CEF-NF with merely 40 wt% of CF and 50 g/m(2) areal density can achieve a specific overall EMI-SE as high as 30.29 dB, or 110 dB.cm(3)/g-meeting commercial EMI requirements. Lastly, the ideal and actual EMI shielding mechanism were fully investigated and analyzed. It was found that the electrical percolation threshold of CEF-NF had a great influence on the actual absorption and reflection performance. At the conductivity threshold, CEF-NF showed high absorption performance. (C) 2017 Elsevier Ltd. All rights reserved.