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- 摘要
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- 实验方案
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Electrical and Electromagnetic Interference (EMI) shielding properties of hexagonal boron nitride nanoparticles reinforced polyvinylidene fluoride nanocomposite films
摘要: The hexagonal boron nitride nanoparticles (h-BNNPs) reinforced flexible polyvinylidene fluoride (PVDF) nanocomposite films were prepared via a simple and versatile solution casting method. The morphological, thermal and electrical properties of h-BNNPs/PVDF nanocomposite films were elucidated. The electromagnetic interference (EMI) shielding properties of prepared nanocomposite films were investigated in the X-band frequency regime (8–12 GHz). The EMI shielding effectiveness (SE) was increased from 1 dB for the PVDF film to 11.21 dB for the h-BNNPs/PVDF nanocomposite film containing 25 wt% h-BNNPs loading. The results suggest that h-BNNPs/PVDF nanocomposite films can be used as lightweight and low-cost EMI shielding materials.
关键词: Hexagonal boron nitride,PVDF,SEM,EMI shielding,DSC,electrical properties
更新于2025-09-23 15:21:21
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Variable densification of reduced graphene oxide foam into multifunctional high-performance graphene paper
摘要: Super-flexible, electrically and thermally conductive graphene-based papers are in great demand in the fields of electronics and supercapacitors. However, the applications of graphene-based papers are limited either by their brittleness, small scale, or by their unsatisfactory thermal conductivity. Conventionally, such papers are fabricated by vacuum-assisted filtration, direct evaporation, electrospray coating, or wet spinning. Here we propose a novel strategy, namely, direct densification of reduced graphene oxide foam, to fabricate large-scale multifunctional graphene papers. The graphene paper density could be adjusted by applying different loads. The densities of the graphene papers varied from 0.32 g cm?3 to 1.85 g cm?3. The thermal conductivity, tensile stress, electrical conductivity and electromagnetic interface shielding effectiveness increased with an increase in the density of the graphene paper. When the density of the graphene paper reached 1.85 g cm?3, the tensile stress was up to 50.4 MPa with strain of 4%, the thermal conductivity was 1103 W m?1 K?1 at room temperature and there was high electrical conductivity of 1.1 × 10? S m?1, as well as an electromagnetic interference (EMI) shielding effectiveness of 77.2 dB. Our new strategy is very promising in terms of controlling the thickness, density, and size of graphene paper.
关键词: graphene paper,densification,EMI shielding,electrical conductivity,thermal conductivity
更新于2025-09-19 17:15:36
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Hybrid composite mats composed of amorphous carbon, zinc oxide nanorods and nickel zinc ferrite for tunable electromagnetic interference shielding
摘要: With the rapid growth of electronics and telecommunication industries, electromagnetic pollution is a serious concern to be addressed because it not only affects the sensitivity and performance of the devices but also affects human’s health. Here, we report lightweight hybrid composite mats, having porosity around 40%, composed of amorphous carbon, zinc oxide nanorods and nickel zinc ferrite for excellent electromagnetic interference (EMI) shielding in the X-band (8.2-12.4 GHz). The vibrating sample magnetometer measurement confirmed that the saturation magnetization value (Ms) of the composite materials enhances with the weight percentage of zinc oxide nanorods-nickel zinc ferrite (ZNF) powder, which leads to enhanced magnetic loss of the electromagnetic waves. With the thickness of 1.0 mm, the total EMI shielding effectiveness of the amorphous carbon composite was measured to be 25.70 dB which was further enhanced to 53 dB by the incorporation of the ZNF powder. Such high increment is attributed to the enhanced magnetic properties, interfacial polarization and dielectric properties of the composite. The synergistic combination of the materials results in the high reflection coefficient and absorption coefficient of the composites which were measured to be ~0.916 and ~0.083, respectively. Thus, the composites can shield up to 99.999% power of the electromagnetic waves which is shared by the 8.394% reflection and 91.605% absorption. Moreover, the magnetic, electrical and EMI shielding properties of the composites can be tuned by controlling the amount of ZNF powder in composites. Hence, the composite mats can be suitable for applications in defense and telecommunication.
关键词: A. Hybrid,A. Nano-structures,EMI shielding,B. Magnetic properties,B. Electrical properties
更新于2025-09-19 17:15:36
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Advanced Materials for Electromagnetic Shielding (Fundamentals, Properties, and Applications) || Silver Nanowires as Shielding Materials
摘要: To date, several advanced materials have been developed in order to resolve the issue of electromagnetic interference (EMI). Among those materials, intrinsic conductive polymers, metal/polymer composites, and conductive filler/polymer composites (CPCs) are the most commonly used and extensively investigated. Metals and their polymeric composites presents high EMI shielding effectiveness, and thus dominate the EMI shielding materials. Being lightweight, processable, and corrosion resistant are important technical requirements for many EMI shielding applications. Intrinsic conductive polymers can well meet these requirements due to their inherent properties. However, their low conductivity largely limited their shielding effectiveness. CPCs, which incorporate the aforementioned properties of polymers and high conductivity of the fillers, have attracted great interest in recent years.
关键词: Silver Nanowires,EMI Shielding Effectiveness,Conductive Composites,Shielding Materials,Electromagnetic Interference
更新于2025-09-04 15:30:14
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Advanced Materials for Electromagnetic Shielding (Fundamentals, Properties, and Applications) || Mechanical Performance Characterization of EMI Shielding Materials Using Optical Experimental Techniques
摘要: In this chapter, the full field optical experimental methods for characterizing the mechanical performance of EMI shielding materials have been discussed. Interest in this type of physical problem is motivated by its importance in many practical applications. One major disadvantage of the use of optical techniques in characterizing the mechanical performance of EMI shielding materials is their full field and noncontact with the materials. The information outlined in this chapter may help researchers and engineers in their study of the unknown features of related complex systems for technological applications in characterizing EMI shielding materials.
关键词: EMI shielding materials,photoelastic method,digital gradient sensing,mechanical performance,moiré interferometry,digital image correlation,coherent gradient sensing,optical experimental techniques
更新于2025-09-04 15:30:14