改性碳系填料填充聚合物基电磁屏蔽复合材料的研究进展

为了满足电子设备轻量化和高度集成化发展的趋势和社会健康需求,轻量化、低成本、耐腐蚀的电磁屏蔽材料日益受到青睐。碳系导电填料,尤其是碳纳米管和石墨烯,在聚合物基电磁屏蔽复合材料中应用广泛。但碳系导电填料颗粒的应用通常因其在聚合物基中有限的分散性使得它们与聚合物基体的相互作用受到障碍,从而对电磁屏蔽效能产生不利影响。文中综述了碳纳米管和石墨烯及相关复合材料的典型改性方式及其电磁屏蔽性能,旨在为其在聚合物基电磁屏蔽复合材料中的应用提供良好的设计思路。     

功能填料表面修饰对聚合物基复合材料电磁屏蔽性能影响研究进展

对于自身不具备电磁屏蔽性能的聚合物材料而言,加入功能填料是赋予其屏蔽性能的主要方法。然而,简单的填充并不能达到上述目的,填料表面的功能化修饰对聚合物基复合材料电磁屏蔽性能具有重要影响。文中总结了填料表面功能化修饰的主要方法,包括化学镀、表面炭化、包覆聚合物、表面接枝和表面生长金属有机骨架（MOF）等,讨论了各种表面修饰对聚合物基复合材料性能产生的改性效果及最终对电磁屏蔽效能的影响,并对相关研究的未来发展提出了建议。     

电磁屏蔽碳系纳米粒子/聚合物基泡沫复合材料的研究进展

各种电子设备的广泛应用,使得电磁辐射与电磁污染日益严重,电磁屏蔽材料应运而生.泡沫复合材料具有密度低,强度高,抗氧化,耐久性强等优点,是一种新型电磁屏蔽材料.本文介绍了电磁屏蔽碳系纳米粒子/聚合物基泡沫复合材料的最新研究进展.基于材料对电磁波的屏蔽机理,重点分析和概述了复合材料中的吸波剂、微观结构及宏观形貌对电磁屏蔽性能的影响.最后对电磁屏蔽碳系纳米粒子/聚合物基泡沫复合材料的未来发展提出了展望.结果表明,对碳系吸波剂进行改性、构建非均匀结构、设计多样化宏观形貌均可提高泡沫复合材料的屏蔽性能.此外,对复杂电磁环境下电磁屏蔽材料的设计与开发具有重要的理论意义.     

电磁屏蔽特种工程塑料制备及应用研究进展

对近年来关于特种工程塑料基电磁屏蔽材料的研究进展进行了综述.重点总结分析了填料选择和结构设计对特种工程塑料基电磁屏蔽复合材料屏蔽效能和屏蔽机理的影响效应.研究人员通过结构设计使填料取向分布,富集连通形成高效导电网络;通过填料选择与改性,改善填料分布、调控材料电导率和磁导率,有效提升了材料的电磁屏蔽性能.另外,提出了电磁屏蔽特种工程塑料的未来研究方向并对其发展前景进行了展望.     

不同金属填料对电磁屏蔽涂料屏蔽效能的影响

复合电磁屏蔽材料是一类用于防护电磁波干扰的新型功能材料,作为屏蔽组分主体的金属填料的电磁特性及其在涂料中的分布状态对于材料的屏蔽效能具有显著的影响,同时由于复合材料的结构特点使这类复合电磁屏蔽材料的屏蔽效能与传统金属板材的屏蔽效能计算理论有着较大的差异.在实验研究的基础上讨论了几种典型的金属粉末填料构成的复合电磁屏蔽材料的屏蔽效能的特点,并分析了其与传统屏蔽效能计算理论的差异和形成的原因,为设计高效复合电磁屏蔽材料提供必要的参考.     

碳系导电填料性质对PVB基功能薄膜结构及电磁屏蔽效能的影响

分别以形状和电导率不同的石墨、镀镍石墨和镀银碳纤维为功能填料,采用溶液流延法制备了聚乙烯醇缩丁醛基导电薄膜,并对薄膜的微观结构和电学性能进行了研究。结果表明:填料性质(包括形状、密度和电导率)对复合材料的分布结构和电学性能有重要影响,纤维状的填料更容易搭接成导电网络。石墨和镀银碳纤维填充体系中,填料在聚合物基体内部分布基本均匀;而镀镍石墨填充体系中,填料在聚合物基体内部形成了梯度分布。不同的分布状态导致材料的导电性能在薄膜的上下表面产生差异并对复合材料的电磁屏蔽效能产生影响。在同等体积含量下,复合材料的电磁屏蔽效能主要受材料电导率的影响,三种复合材料中,镀银碳纤维填充体系的屏蔽效能最高,镀镍石墨填充体系次之,石墨填充体系最低。     

电磁屏蔽复合材料的屏蔽性能预测

建立了填充椭球颗粒电磁屏蔽复合材料等效电磁参数的物理模型,基于变分原理和电磁波传输理论推导出其电磁屏蔽性能的预测公式,计算了不同填充条件下复合材料的屏蔽效能及反射率,分析了填料显微结构特征(浓度、形状、尺寸、分布方式)对复合材料屏蔽性能的影响规律.结果表明,复合材料屏蔽效能和反射率随填料填充浓度、长径比的增加而增大;针形和片形填料优于球形填料且定向分布好于随机分布;材料的反射率在特定的填充浓度及填料尺寸下存在峰值。屏蔽效能的计算结果与实验上填充球形银包羰基铁和镀镍短碳纤维的屏蔽复合材料的测试数据拟合较好。     

聚合物基电磁屏蔽涂层的组成、结构与性能

介绍了聚合物基电磁屏蔽涂层的分类和屏蔽机理,重点讨论了电磁屏蔽涂层的组成、结构与性能的关系,展望了电磁屏蔽涂层的发展趋势.     

电磁屏蔽聚合物复合泡沫材料的制备及研究进展

综述了聚合物复合泡沫材料的最新应用进展，详细介绍了聚合物复合泡沫材料在电磁屏蔽领域的研究现状。首先概述了聚合物复合泡沫材料的不同制备方法，重点分析了不同填料、孔隙结构、材料厚度对电磁屏蔽性能的影响。最后介绍了聚合物复合泡沫材料在电磁屏蔽材料领域中的应用，并对其未来发展进行了展望。     

聚合物基X射线屏蔽复合材料研究进展

随着医用X射线及核能工业的快速发展,X射线屏蔽材料的研究与开发得到了广泛的重视.特别是聚合物作为粘结剂以来,聚合物基屏蔽复合材料克服了铅与钨金属材料的加工缺点,得到迅速发展.本文首先介绍了X射线屏蔽机理及复合材料设计理论,然后综述了聚合物屏蔽材料的研究现状,最后对新型聚合物基复合材料进行了展望.     

电磁屏蔽用聚合物基碳纳米复合材料的构筑

随着通信技术和电子设备的迅速发展,电磁污染已经影响到电子设备正常运行和人类生命安全。因此,开发电磁屏蔽材料具有重大的科学意义。近几年,聚合物基碳纳米复合材料在电磁屏蔽领域迅猛发展,表现出诸多优异的性能,引起学术界的广泛关注。基于本课题组在电磁屏蔽领域的认识和研究,简要介绍了电磁屏蔽原理和聚合物基碳纳米复合材料的制备方法,重点介绍了回填法制备聚合物基碳纳米复合材料的研究进展,最后对电磁屏蔽材料未来的发展趋势和应用提出了展望。     

Recent progress in the modification of carbon materials and their application in composites for electromagnetic interference shielding

With the development in the modern technologies such as telecommunication instruments and scientific electronic devices, large amount of the electromagnetic radiations are produced, which lead to harmful effect on the highly sensitive electronic devices as well as on the health of human beings. To minimize the effect of electromagnetic radiations produced by different technologies, more efficient shielding materials are required which must be cost-effective, lightweight and good corrosion resistive. In this review, we focused on the shielding materials based on composites of carbon nanotubes and graphene. The typical surface modification of carbon nanotubes and graphene to optimize their interactions with polymers matrix has also summarized. It was found that the composites based on these carbon fillers were more efficient for electromagnetic interference shielding due to their unique properties (i.e., superior electrical, mechanical and thermal) together with lightweight, easy processing. Hence, the carbon nanotubes and graphene-based composites are excellent shielding materials against the electromagnetic radiations.     

Electromagnetic shielding effectiveness of copper/glass fiber knitted fabric reinforced polypropylene composites

The main objectives of this research work are to develop conductive knitted fabric composite materials and to determine their electromagnetic shielding effectiveness (EMSE). Polypropylene is the matrix phase and glass fibers are the reinforcement phase of the composite material. Copper wires are incorporated as conductive fillers to provide the electromagnetic shielding properties of the composite material. The amount of copper in the composite material is varied by changing the yarn composition, fabric knit structure and stitch density. The EMSE of various knitted fabric composites is measured in the frequency range of 300 kHz to 3 GHz. The variations of EMSE of knitted fabric composites with fabric structure, stitch density and yarn compositions are described. Suitability of conductive knitted fabric composites for electromagnetic shielding applications is also discussed.     

合成纤维复合夹层屏蔽结构改性及其电磁特性研究

提出具有复合介质夹层屏蔽结构模型的设想,利用铜箔-聚四氟乙烯为原材料,设计了单层屏蔽结构与复合夹层屏蔽结构的对比实验,测试了复合夹层屏蔽结构的电磁屏蔽效能增量,并用Ватолцн多层电磁屏蔽理论公式进行了验证。具有复合夹层屏蔽结构材料的电磁屏蔽效能明显优于单层屏蔽结构材料的电磁屏蔽效能。继而以涤纶无纺布、锦纶合成纤维为研究对象,采用电化学改性的方法,制备了具有复合夹层屏蔽结构的柔性电磁屏蔽材料。结果表明,通过对研究对象的选择和优化电化学改性的工艺,可以制备出1 MHz~1000 MHz入射电磁波频段范围内,满足不同要求的合成纤维复合夹层屏蔽结构改性材料,其SE值最高可达98 dB。     

石墨烯纳米片/聚乙烯复合薄膜电磁干扰屏蔽

研制了一种取向性较高的石墨烯纳米片/低密度聚乙烯（GNS/LDPE）复合薄膜三明治结构,分析其电磁干扰屏蔽（EMIS）性能和机制。实验结果表明,GNS/LDPE复合薄膜的EMIS性能主要决定于其电学性质。根据材料电导率对多层复合膜进行理论计算,探讨GNS/LDPE复合薄膜多层结构的光吸收和多层反射机制。通过调整层结构的厚度和表面层深度及屏蔽材料的电导率可以提高EMIS性能,并且增加屏蔽层厚度可增强吸收屏蔽作用从而进一步提高总屏蔽性能。结构优化后的EMIS效率可以达到31 dB,证明GNS/LDPE复合薄膜具有显著的EMIS作用。纳米复合三明治结构的屏蔽机制为设计高EMIS性能纳米复合物提供了基本依据。提出了实现高性能GNS/LDPE复合薄膜的有效技术方法,在EMIS涂层领域具有潜在的应用。      

Electrical and impact properties of the hybrid knitted inlaid fabric reinforced polypropylene composites

A range of conductive knitted fabric reinforced polypropylene composites have been developed and their electromagnetic shielding effectiveness (EMSE), electrostatic discharge (ESD) and impact properties have been investigated. Carbon and aramid fibers are used as the reinforcement phase in the composites, while copper and stainless steel wires are incorporated as conductive fillers to provide the ESD and EMSE properties of the composite materials. The hollow spindle spinning system has been used to make SS/PP, Cu/PP, SS/C/PP, Cu/C/PP and Cu/K/PP uncommingled yarns. The double plain knitted fabric and its inlaid fabrics were fabricated from the yarns using a 5G traverse knitted machine. Changing the yarn composition, fabric knit structure, and stitch density varies the amount of copper and stainless steel conductive fillers in the composites. 4 layer cross-ply laminates were laid-up by hand, then formed into 3-mm thick conductive thermoplastic composites using a compression molding. It was observed that the EMSE and ESD of the composites increase with increasing the incident frequency, especially at higher frequency range. The effects of inlaid ends, materials and yarn constitutions on the EMSE of the conductive thermoplastic composites were investigated. The results indicate that the composites can be used for the purpose of electromagnetic shielding and ESD attenuation, as well as for some microwave applications.     

Foamed poly(lactic acid) composites with carbonaceous fillers for electromagnetic shielding

Electromagnetic shielding is one the key factors for electronic devices in their use and transportation. Polylactide (PLA) is a biodegradable polymer with a moderate biodegradability and decent mechanical properties. Replacement of traditional materials by biodegradable polymers brings about the fossil resources savings and helps solving problems related to the plastic packaging waste. In this work composites of PLA with carbon black and carbon nanofibers were described. Improvement of the material mass/electromagnetic interference SE (shielding effectiveness) ratio can be obtained by introducing foaming technology into the material preparation process. Microporous structure can greatly improve material properties such as thermal isolation, mechanical properties and in case of composites filled with carbonaceous fillers such as carbon black carbon fibres – also the electrical conductivity.In order to improve their application range and reduce density, a cellular structure was created using chemical blowing agent. It was found that in low loaded composites (although above the percolation level) the shielding effectiveness relies on the amount of a conductive filler but it may be additionally enhanced by the foaming process. Electrical properties, electromagnetic shielding effectiveness and morphology of cellular composites for described polymer-filler systems have been presented.     

可用于包装的纤维素基电磁屏蔽材料研究进展

目的 为推动可用于包装的纤维素基电磁干扰(Electromagnetic Interference,EMI)屏蔽材料更深入的研究,综述一些具有包装材料潜质和EMI屏蔽功能的纤维素基薄膜、织物和气凝胶的最新研究进展。方法 主要介绍纤维素基薄膜、织物和气凝胶等3类EMI屏蔽材料的制备方法、EMI屏蔽性能、多功能性和在包装上应用的潜力。结果 当下纤维素基EMI屏蔽材料表现出令人满意的EMI屏蔽效能(EMI Shielding Effectiveness, EMI SE)和力学性能,有望作为包装材料。同时一些材料还显示出抗菌、隔热、抗冲击等特性,使得这些材料能在复杂的场景下应用。结论 通过合理的设计,纤维素基EMI屏蔽材料可拥有优异的EMI屏蔽性能、出色的力学性能和良好的耐用性。归因于上述优势和绿色可降解的特性,这类材料有望在未来取代传统的EMI屏蔽包装材料,然而这些材料通常需要精细的制备工艺,材料的量产和实际应用依然是亟待解决的问题。     

电磁屏蔽复合材料电磁屏蔽效能探讨

电磁屏蔽材料目前向着薄、轻、宽、高的方向发展,复合材料已逐渐取代单一材料成为电磁屏蔽研究的主要方向.以机械复合材料为基础,研究高导电材料+高导磁2层复合材料与高导电材料+高导电材料+高导磁材料3层复合材料电磁屏蔽效能的差别.研究结果表明,2层复合材料高导电材料一侧增加1层高导电材料对电磁屏蔽性能的提高非常有限.