电磁屏蔽橡胶复合材料的研究进展

介绍电磁屏蔽橡胶复合材料及其所用胶种(天然橡胶、丁苯橡胶、三元乙丙橡胶、丁基橡胶和硅橡胶等)及电磁屏蔽填料[导电填料(金属和镀金属填料、导电炭黑、碳纤维、碳纳米管、石墨烯等)和吸波填料(铁氧体和羰基铁粉等)]的研究状况,并概述新型立体导电骨架结构电磁屏蔽复合材料的特征,指出电磁屏蔽橡胶复合材料的导电和吸波机理、结构以及橡胶与填料之间的界面作用等是今后的研究重点。     

铜系电磁屏蔽涂料的研究

阐述了电磁屏蔽涂料的电磁屏蔽原理和导电机理;讨论了导电填料的填充量、形状、粒度和填充型导电涂料导电性能的关系;分析了偶联剂、镀覆金属、漆膜厚度及固化条件对导电涂料的导电性能的影响;提出了铜系导电涂料尚需解决的主要问题。     

电磁辐射与电磁屏蔽涂料的应用

综述了电磁辐射引起的影响及能屏蔽电磁辐射涂料的组成与应用。屏蔽涂料可用金属导电粉为填料与高分子材料混合而构成。介绍了导电涂料在电磁屏蔽领域里的应用与发展趋势。     

纳米导电和电磁屏蔽涂料特性表征和评价方法

纳米导电和电磁屏蔽涂料特性表征方法为测定导电填料类型,包括金属系类型、碳系类型、金属氧化物类型以及复合物类型等;评价方法为测定漆膜的表面电阻、表面电阻率、体积电阻和体积电阻率或电磁屏蔽效能。文章对纳米涂料导电和电磁屏蔽特性的表征和评价方法进行探讨。     

碳纳米管涂料的研究进展

综述了碳纳米管涂料的最新研究进展,介绍了碳纳米管在复合材料、导电、电磁屏蔽、吸波、吸热、抗菌等特殊涂料中的应用。初步探讨了碳纳米管涂料特殊性能的机理,指出了纳米涂料产业化所面临的困难,并对今后的发展进行了展望。     

碳系填料在聚合物基导电复合材料中的应用

介绍碳系填料在聚合物基导电复合材料中的应用以及导电复合材料渗流阈值的影响因素。碳系填料主要包括炭黑、石墨、碳纤维和碳纳米管等,对各类碳系填料的研究应侧重于提高其本征导电性能,并解决填料在聚合物基体中的分散问题。开发复合填料是拓宽碳系填料在电磁屏蔽领域应用的有效途径。采用混合填料、复合填料和多种聚合物材料并用可显著降低复合材料的电阻率,提高电磁屏蔽性能,降低导电渗流阈值。     

掺杂型电磁屏蔽导电涂料研究进展

电磁屏蔽导电涂料是应用广泛的防电磁辐射材料之一,本文概述了电磁屏蔽导电涂料的屏蔽原理及类型,分析了掺杂型电磁屏蔽导电涂料国内外研究现状以及存在的主要问题,对电磁屏蔽导电涂料的发展趋势及研究开发的重点进行了展望.     

电磁屏蔽涂料用复合型导电填料研究进展

回顾了电磁屏蔽涂料用复合导电填料的现状和应用,并对比了各种类型复合导电填料的优缺点,重点阐述了复合碳纤维用作导电填料的优缺点及其应用。针对目前该类型填料高反射低吸收、分散性和亲和性等方面的不足,提出了解决方案。最后分析了复合型导电填料设计的影响因素。     

基于机械球磨法的茂金属PE/石墨/碳纳米管导电复合材料的制备及性能研究

以茂金属PE为基体,以石墨和碳纳米管为导电填料,采用机械球磨法,制备茂金属PE/石墨/碳纳米管导电复合材料,考察球磨时间、球磨温度、球磨转速和石墨含量等对复合材料导电性的影响。结果表明,在球磨时间60 min,球磨温度50℃,球磨转速150 r/min、导电填料15%石墨、5%碳纳米管的条件下,复合材料的电阻率降到1.36Ω·cm,可作为一种电磁屏蔽材料应用于电子元器件表面。     

基于机械球磨法的茂金属PE/石墨/碳纳米管导电复合材料的制备及性能研究

以茂金属PE为基体,以石墨和碳纳米管为导电填料,采用机械球磨法,制备茂金属PE/石墨/碳纳米管导电复合材料,考察球磨时间、球磨温度、球磨转速和石墨含量等对复合材料导电性的影响。结果表明,在球磨时间60 min,球磨温度50℃,球磨转速150 r/min、导电填料15%石墨、5%碳纳米管的条件下,复合材料的电阻率降到1.36Ω·cm,可作为一种电磁屏蔽材料应用于电子元器件表面。     

炭系填料／水性叔氟导电涂料的性能研究

用石墨、膨胀石墨、碳纤维三种不同的炭系填料制备了既环保、又具有比一般涂料更优异的性能的水性叔氟导电涂料。经研究发现,在填料含量相同的条件下,碳纤维的涂层较石墨、膨胀石墨的导电性高,其原因在于其不同构型的导电粒子在涂层中形成的导电网络不同。     

CNT/mica导静电防腐蚀涂料的研制

以碳纳米管复合导电云母(CNT/mica)为填料、水性环氧树脂为基体制备了导静电防腐蚀涂料;CNT/mica具有易分散、用量低、制得的漆膜综合性能优异等优点,为碳纳米管的广泛应用开创了新局面。     

The influence of carbon nanotube aspect ratio on the foam morphology of MWNT/PMMA nanocomposite foams

Polymer nanocomposite foams, products from the foaming of polymer nanocomposites, have received increasing attention in both the scientific and industrial communities. Nanocomposite foams filled with carbon nanofibers or carbon nanotubes with high electrical conductivity, enhanced mechanical properties, and low density are potential effective electromagnetic interference (EMI) shielding materials. The EMI shielding efficiency depends on the electrical conductivity and bubble density, which in turn, depend on the properties of the filler. In the current study, multi walled carbon nanotubes (MWNT) with controlled aspect ratio were used to alter the bubble density in MWNT/poly(methyl methacrylate) (PMMA) nanocomposites. It was found that the nanocomposite foams filled with shorter MWNT had higher bubble density under the same foaming conditions and MWNT concentration. Both the ends and sidewalls of carbon nanotubes can act as heterogeneous bubble nucleation sites, but the ends are more effective compared to the sidewalls. Shorter nanotubes provide more ends at constant MWNT concentration compared to long nanotubes. As a result, the difference in the foam morphology, particularly the bubble density, is due to the difference in the number of effective bubble nucleation sites.     

电磁屏蔽与导电胶粘剂研制

介绍了导电胶粘剂的导电机理,讨论了导电载体(填料)的类型、形状以及粘料(树脂)等对导电胶粘剂性能的影响。根据电磁屏蔽产品的性能要求和成型工艺条件,研制出一种能满足电磁屏蔽要求的环氧-银粉型导电胶粘剂。     

Optically transparent polymer composites: A study on the influence of filler/dopant on electromagnetic interference shielding mechanism

Composite materials made of polymers and carbon-based ferromagnetic filler are attractive for electromagnetic interference shielding through a combination of reflection and microwave absorption. It is possible to enhance their shielding properties by controlling electrical conductivity, dielectric, and magnetic properties. In this work, the aforementioned properties are tailored to achieve optically transparent films with microwave absorbing properties. Nanocarbon materials, namely carbon nanotubes, graphene nanoribbons (GNR) and their ferromagnetic nanocomposites with Fe₃O₄ and cobalt in PVA-PEDOT:PSS matrix were made and tested in X-band. The highest shielding effectiveness for PVA films with nanocarbon filler was observed for 0.5 wt% GNR − Fe₃O₄ at 16.36 dB (9.7 GHz) with 79.8% transmittance.     

碳纳米管填料静电自组装制备及在导电塑料中的应用

为了提高碳纳米管(CNTs)在塑料中的分散性能,设计碳纳米管填料(CNTs Filler)。阳/非离子表面活性剂复配在水中分散CNTs,并赋予CNTs表面正电性。与表面负电性的炭黑或聚苯乙烯微球复合,通过静电吸附作用自组装形成均匀稳定的复合物,制备出CNTs Filler。对比了CNTs Filler、CNTs和炭黑在PS和ABS塑料中,经不同成型工艺的导电结果,证明了使用碳纳米管填料提高了碳纳米管在塑料中的分散性能,总结了碳纳米管相对炭黑作为塑料导电功能体适合压延成型加工。推荐碳纳米管用于导电片材、导电薄膜和高导电塑料等领域。     

Thermally stable electromagnetic interference shielding material from polysulfone nanocomposites: Comparison on carbon nanotube and nanofiber reinforcement

The present investigation aims to develop thermally stable electromagnetic interference shielding materials from polysulfone (PSU) nanocomposites filled with multiwall carbon nanotubes (MWCNT) or carbon nanofibers (CNF). The effect of filler type and their structural features such as aspect ratio (length/diameter) and wall integrity on the different properties of nanocomposites has been investigated. Nanocomposite filled with MWCNT/CNF exhibits higher thermal stability compared with the neat PSU matrix. The onset degradation temperature of PSU at 532°C enhances to 537 and 538°C at 3 wt% MWCNT and 3 wt% CNF loading, respectively. CNFs filled nanocomposite shows higher electromagnetic interference shielding effectiveness (EMISE) compared with MWCNT filled one at the same filler loading. Compared with MWCNT, CNF imparts lower electrical percolation threshold. Nanocomposite filled with MWCNTs possesses percolation threshold at 1.5 wt%, whereas nanocomposite filled with CNFs possesses the same at 0.9 wt%. The EMISE of 20–45 dB are obtained from only 1 mm thick CNF filled nanocomposites from the filler loading 3 to 10 wt%. This value of EMISE above 40 dB suggests that the prepared nanocomposite can be used as an effective lightweight EMI shielding material for high frequency (8.2–12.4 GHz) applications, where high thermal stability is required. POLYM. COMPOS. 36:566–575, 2015. © 2014 Society of Plastics Engineers     

Factorial design approach applied to electrically and thermally conductive nylon 6,6

Increasing the thermal and electrical conductivity of typically insulating polymers, such as nylon 6,6, opens new markets. A thermally conductive resin can be used for heat sink applications. An electrically conductive resin can be used in static dissipative and Electromagnetic Interference/Radio Frequency Interference shielding applications. This research focused on performing compounding runs followed by injection molding and testing (tensile properties, volumetric electrical resistivity, and through‐plane thermal conductivity) of carbon filled nylon 6,6. The four carbon fillers investigated included a PAN‐based carbon fiber (milled, 200μ long), an electrically conductive carbon black, vapor grown graphitic nanotubes, and Thermocarb (high quality synthetic milled graphite). Formulations were produced and tested that contained varying amounts of a single carbon filler. Combinations of fillers were also investigated via conducting half of a 2⁴ factorial design. It was determined that Thermocarb has the largest effect on the thermal conductivity. Increasing Thermocarb increases thermal conductivity. For conductive resins containing only a single filler type, nanotubes caused the electrical resistivity (ER) to decrease the most. For the half fraction factorial design formulations that contain at least one filler type at the higher level, the ER of the conductive resin ranged from 0.1 to 0.3 ohm‐cm.     

玻璃纤维化学镀银的工艺研究

采用AgNO3活化剂代替传统的PdCl2,进行化学镀银包覆玻璃纤维降低了工艺成本;通过超声波粗化、敏化、活化等工艺对玻璃纤维进行了前处理,讨论了主盐、还原剂、pH等因素对化学镀银沉积速度、电阻率及镀层含量的影响,从而确定了最佳的工艺配方。使低密度的银包玻璃纤维作为导电高分子材料用于电磁屏蔽中。     

导电高分子复合材料的电磁屏蔽效能分析

本文分析了电磁屏蔽的基本原理,着重探讨了导电填料、高分子基体以及复合工艺等因素对导电高分子复合材料电磁屏蔽效能的影响。