Composite Shield Research Articles

Stretchable liquid metal grid/metallized polyurethane composites with switchable electromagnetic interference shielding and efficient infrared stealth performance

Intelligent electromagnetic interference (EMI) shielding materials with tunable electromagnetic shielding properties becomes a significant and urgent concern for information society. Hence, a switchable and low-reflectivity EMI shielding composite is fabricated by electroless nickel plating on the surface of polyurethane nonwoven fabric (Ni@TPU), and followed by combining with liquid metal (LM) grid. The synergistic combination of Ni@TPU and LM grid effectively facilitates the rational construction of hierarchical impedance matching. Meanwhile, it promotes destructive interference between electromagnetic waves reflected from Ni@TPU and the LM grid. As a result, an excellent low-reflectivity EMI shielding performance can be achieved. More importantly, the switchable EMI shielding performance can be easily realized by repeatedly stretching Ni@TPU/LM. In addition, the fluffy nonwoven fabric and LM grid with low infrared emissivity endow it with an outstanding infrared stealth performance. Such excellent low-reflectivity EMI shielding switch performance incorporated with flexible infrared stealth makes it possible to become smart EMI shielding material with a great promise to be employed in the application scenario of window in camouflage container.

Research on B4C/PEEK Composite Material Radiation Shielding

There are various types of charged particles in the space environment, which can cause different types of radiation damage to materials and devices, leading to on-orbit failures and even accidents for spacecraft. Developing lightweight and efficient radiation-shielding materials is an effective approach to improving the inherent protection of spacecraft. The protective performance of different materials against proton and electron spectra in the Earth’s radiation belts is evaluated using a Geant4 simulation. Based on the simulation results, suitable hardening components were selected to design composite materials, and B4C/PEEK composites with different B4C contents were successfully prepared. The experimental results demonstrate that the simulated and experimental results for the electron, proton and neutron shielding performance of the B4C/PEEK composites are consistent. These composites exhibit excellent radiation shielding capabilities against electrons, protons and neutrons, and the radiation protection performance improves with increasing B4C content in the B4C/PEEK composite materials.

Development and characterization of highly conductive hybrid Moringa oleifera husk biocarbon and grape pulp cobalt oxide polyvinyl alcohol composites for microwave shielding

Development and characterization of highly conductive hybrid Moringa oleifera husk biocarbon and grape pulp cobalt oxide polyvinyl alcohol composites for microwave shielding

Influence of Conductive Filler Types on the Ratio of Reflection and Absorption Properties in Cement-Based EMI Shielding Composites

The growing importance of electromagnetic interference (EMI) shielding composites in civil engineering has garnered increasing attention. Conductive cement-based composites, incorporating various conductive fillers, such as carbon nanotubes (CNTs), carbon fibers (CFs), and graphene nanoplatelets (GNPs), provide effective solutions due to their high electrical conductivity. While previous studies have primarily focused on improving the overall shielding effectiveness, this research emphasizes balancing the reflection and absorption properties. The experimental results demonstrate an EMI shielding performance exceeding 50 dB, revealing that filler size (nano, micro, or macro) and shape (platelet or fiber) significantly influence both reflection and absorption characteristics. Based on a comprehensive evaluation of the shielding properties, this study highlights the need to consider factors such as reflection versus absorption losses and filler shape or type when optimizing filler content to develop effective cement-based EMI shielding composites.

Shape of fragments cloud behind heterogeneous screen by a space debris particle impact

Technogenic pollution of near-Earth space poses a threat to the functioning of spacecraft. Collisions between space debris (SD) and spacecraft (SC) structures can have catastrophic consequences or cause localized damage, leading to the loss of SC operability or the failure of certain functions. The SC body must effectively protect the internal equipment from various external impacts, be technologically feasible to manufacture, and have as little mass as possible. As a result, the task of designing spacecraft bodies and protective screens for low-orbit SC is particularly relevant due to the large concentration of SD in low Earth orbits.A comparative numerical study was conducted to evaluate the effectiveness of various thin shields in protecting against impacts from space debris particles. The study examined homogeneous shields made of A356 aluminum alloy and 316L stainless steel, as well as volumetrically reinforced composite shields produced using additive manufacturing with steel inclusions, and shields with a gradient distribution of steel throughout the thickness of an aluminum matrix, all with the same areal density. In all the heterogeneous plates considered, the volumetric concentration of steel was 36 %. The study covered an interaction velocity range of 2–9 km/s. Numerical modeling results indicated that the structure of the thin heterogeneous plate does not affect the shape of the debris cloud formed behind the protective shield. The findings of this study can serve as a basis for selecting materials for the development of more effective protection for spacecraft against high-velocity impacts.

Nacre-like Anisotropic Multifunctional Aramid Nanofiber Composites for Electromagnetic Interference Shielding, Thermal Management, and Strain Sensing.

Developing multifunctional flexible composites with high-performance electromagnetic interference (EMI) shielding, thermal management, and sensing capacity is urgently required but challenging for next-generation smart electronic devices. Herein, novel nacre-like aramid nanofibers (ANFs)-based composite films with an anisotropic layered microstructure were prepared via vacuum-assisted filtration and hot-pressing. The formed 3D conductive skeleton enabled fast electron and phonon transport pathways in the composite films. As a result, the composite films showed a high electrical conductivity of 71.53 S/cm and an outstanding thermal conductivity of 6.4 W/m·K when the mass ratio of ANFs to MXene/AgNWs was 10:8. The excellent electrical properties and multi-layered structure endowed the composite films with superior EMI shielding performance and remarkable Joule heating performance, with a surface temperature of 78.3 °C at a voltage of 2.5 V. Additionally, it was found that the composite films also exhibited excellent mechanical properties and outstanding flame resistance. Moreover, the composite films could be further designed as strain sensors, which show great promise in monitoring real-time signals for human motion. These satisfactory results may open up a new opportunity for EMI shielding, thermal management, and sensing applications in wearable electronic devices.

Liquid metal induced segregated-like electromagnetic shielding composites with excellent photothermal conversion and strain sensing capacities

The development of multifunctional electromagnetic interference (EMI) shielding materials has garnered significant attention, yet achieving flexible composites that integrate EMI shielding, thermal conductivity, and other functionalities under low filler loading remains a challenge. This study presents a novel flexible composite with segregated structure prepared via a simple co-mixing and hot-pressing method. By selectively distributing conductive Liquid metal (LM) and Multi-wall carbon nanotube (CNT) on the surface of Polyurethane (TPU) particles, a continuous and compact conductive network is successfully constructed, enabling the attainment of a high EMI shielding effectiveness of 80.2 dB and a thermal conductivity of 4.8 W m−1 K−1 even at low LM loadings. Furthermore, the composite exhibits low-voltage-driven Joule heating performance, excellent photothermal conversion efficiency, and promising potential for wearable sensor applications. The combination of these outstanding properties highlights the great potential of LM-based composites for next-generation wearable devices.

Advances in the structure and preparation of electromagnetic shielding composites with carbon-based filler polymers

The growth of electronic equipment applications, such as aerospace weaponry, wireless base stations, and 5G communication technologies, has led to serious electromagnetic interference (EMI) and pollution problems. These issues can cause equipment overload and damage. Carbon-based fillers are commonly used as conductive fillers in EMI shielding materials due to their low cost, lightweight and flexible nature, high thermal and electrical conductivity, corrosion resistance, and ease of processing and molding. This paper aims to provide theoretical support for future research by identifying the major trends in the recent advancements of carbon-based filler polymer composites for electromagnetic shielding from the years 2020 to 2024, specifically in filler selection, multifunctional interface design, and preparation methods. Furthermore, this paper discusses the shielding principle of EMI shielding materials, the influence of different kinds of carbon-based fillers on the EMI shielding effect of polymer matrix composites, and the challenges and progress of their preparation methods. In the end, it concludes by proposing future research directions to overcome current technological barriers and further develop EMI shielding materials for industrial applications.

Progress in the preparation of polymer-based MXene-enhanced electromagnetic shielding composites by electrospinning

Progress in the preparation of polymer-based MXene-enhanced electromagnetic shielding composites by electrospinning

MXene Composite Electromagnetic Shielding Materials: The Latest Research Status.

MXene emerges as a premier candidate for electromagnetic shielding owing to its unique properties as a novel two-dimensional material. Its exceptional electrical conductivity, chemical reactivity, surface tunability, and facile processing render it highly suitable for diverse electromagnetic shielding applications. The research status of MXene and MXene-based electromagnetic shielding materials is systematically discussed in this paper. First, the research status of MXene as a single-component electromagnetic shielding material is briefly introduced. Subsequently, the research status of composite structures constructed by MXene with polymers, carbon derivatives, and ferrites is introduced in detail. Furthermore, the research progress of MXene-based ternary and quaternary composite electromagnetic shielding materials is further focused. Finally, the application of MXene-based composite electromagnetic shielding materials is prospected. A deeper understanding of MXene's electromagnetic shielding properties is facilitated by this paper, providing the direction for the future development of two-dimensional materials in the design and processing of electromagnetic shielding materials.

Energy and time characterization of the newly acquired clover detector in Jordan

A comprehensive overview of the Balqarad clover detector acquired by Al-Balqa Applied University in Jordan is given in detail. The detector consists of four high-purity germanium crystals, accompanied by a composite scintillation active shield. Through meticulous testing involving a range of radioactive sources such as 137Cs, 60Co, and 241Am, we evaluate the performance of the clover detector. The associated digital data acquisition system incorporates specialized and unconventional time registers, operating in event-by-event mode. Our objective is to elucidate the energy and time characteristics exhibited by the new system under different operational modes, employing specifically designed offline software. Our findings encompass vital aspects. These aspects include the determination of the optimal time window value for processing data obtained from gamma detection measurements. Another issue that has been considered is the analysis of hit pattern distribution within each individual crystal. Additionally, we calculate the addback factor for the 60Co source, accounting for gamma energies of 1173 keV and 1332 keV while also considering the influence of time window increment.

Synergistic effects of Gd2O3 and SiO2 in enhancing the acoustic, mechanical, and shielding qualities of borate glasses

This study comprehensively analyzes the gamma radiation shielding, mechanical, and acoustic properties of novel glass composites formulated from B2O3, SiO2, and Gd2O3. Utilizing the MCNPX simulation code and Phy-X: PSD software, key parameters such as Linear Attenuation Coefficient, Half Value Layer (HVL), Mean Free Path (MFP), and Effective Atomic Number (Zeff) were meticulously evaluated for three distinct glass compositions, denoted as GL-1, GL-2, and GL-3. The investigation revealed that incorporating Gd2O3 and SiO2 notably enhances the radiation shielding efficiency of these glasses, which is evident from the decreasing trends in HVL and MFP values across the series. Employing the Makishima and Mackenzie (MM) model, this study further delved into the mechanical and acoustic characteristics of the glass samples. An increase in Gd2O3 and SiO2 content, substituting B2O3, was observed to augment the bond dissociation energy and adjust the packing density, consequently improving the elastic moduli. These mechanical enhancements were quantified through measurements of Young's modulus, bulk modulus, shear modulus, and longitudinal modulus. Acoustic properties were also calculated, including Longitudinal and Transverse velocities, mean velocity, and acoustic impedance. These parameters demonstrated a consistent improvement correlating with the increasing rigidity and mechanical strength of the glass samples, particularly for the GL-3 composition. The study concludes that the GL-3 glass sample exhibits superior performance regarding gamma photon attenuation, mechanical robustness, and acoustic properties. This underscores its potential as an effective material for radiation shielding in various industrial applications, benefiting from its enhanced mechanical and acoustic features.

Fe3O4@CNTs/WPU@CNF aerogel/Ag foam composites with a double-layer structure for absorption-dominated electromagnetic shielding performance

With the popularity of electronic devices, absorption-dominated multilayered electromagnetic shielding materials are increasingly attractive due to the effective decrease of second pollution compared to the traditional homogeneous electromagnetic shielding materials. However, the design of multilayered structure and strong interface adhesion of functional composite while keeping light weight and practical use is not readily to realize. Therefore, we propose herein a double-layer aerogel/foam composite electromagnetic shielding composite. The absorption layer is made by a nanocellulose (CNF)@waterborne polyurethane (WPU) aerogel, in which magnetic nano iron tetraoxide (Fe3O4) joined with carbon nanotubes (CNTs) to optimize the impedance matching. The reflection layer is a chemically silver-plated foam (AF) used to reflect the transmitted electromagnetic waves through its strong electrical conductivity, improving the overall ability of electromagnetic waves shielding and achieving enhanced electromagnetic shielding performance. The two layers are strongly combined by the adhesion of WPU without the use of adhesives. When the mass ratio of CNTs to Fe3O4 of 2:1 and the total mass fraction of 5 wt%, the EMI shielding efficiency of the composites reaches 62.81 dB in the X-band (8.2–12.4 GHz) at the thickness of 4 mm and the maximum value reaches a remarkable 76.63 dB at 1.17 GHz. The specific SE value of SSE/t reaches 1744.72 dB cm2 g−1. Thanks to the effect of AF layer, the average reflectivity is only 0.141, demonstrating an absorption-dominated shielding mechanism. In addition, the as-prepared composite material is remarkably flexible and deformation-resistant, with a density of only 0.0913 g cm−3 and can withstand approximately 85,000 times its own weight.

Evaluation of radiation shielding performance: comparison of lead and polyvinylidene difluoride reinforced with tungsten

This study examines the shielding properties of polyvinylidene difluoride reinforced with 20%, 40%, and 60% weight fractions of tungsten and compares the findings to those obtained from lead. The mass and linear attenuation coefficient, half-value layer, and effective atomic number were calculated using the Phy-X/PSD software. From the photon interactions with matter point of view, the Photoelectric effect dominates in low-energy photons, while pair production is dominant in high-energy photons; meanwhile, Compton scattering remains almost constant across the energy range. The results show that the mass attenuation coefficient is higher for low-energy photons, and composites with a higher weight fraction of tungsten exhibit higher values of mass attenuation coefficients. The half-value layer decreased as the weight fraction of tungsten increased, and the effective atomic number was higher for lower energy photons. These findings were contrasted against calculations derived for lead. Within the energy interval of 20–200 keV, the mass attenuation coefficient for lead was observed to be approximately two times that of the optimal values recorded for the specific composites under examination, whereas at 2 MeV, this discrepancy diminished. The minimum half-value layer for polyvinylidene difluoride augmented with 60% weight proportions of tungsten in comparison to lead was identified at an energy of 2 MeV. During this interval, the half-value layer for this composite material was threefold greater than that of lead. Although the mass attenuation coefficient is higher for lead, in some energy ranges (about two MeV), the findings from the selected composites are completely comparable to those from lead, demonstrating the ability and performance of the polyvinylidene difluoride composites for radiation shielding.

3D Printing of Composite Radiation Shielding for Broad Spectrum Protection of Electronic Systems.

The miniaturization of satellite systems has compounded the need to protect microelectronic components from damaging radiation. Current approaches to mitigate this damage, such as indiscriminate mass shielding, built-in redundancies, and radiation-hardened electronics, introduce high size, weight, power, and cost penalties that impact the overall performance of the satellite or launch opportunities. Additive manufacturing provides an appealing strategy to deposit radiation shielding only on susceptible components within an electronic assembly. Here, a versatile material platform and process to conformally print customized composite inks at room temperature directly and selectively onto commercial-off-the-shelf electronics is described. The suite of inks uses a flexible styrene-isoprene-styrene block copolymer binder that can be filled with particles of different atomic densities for diverging radiation shielding capabilities. Additionally, the system enables the combination of multiple distinct particle species within the same printed structure. The method can produce graded shielding that offers improved radiation attenuation by tailoring both shield geometry and composition to provide comprehensive protection from a broad range of radiation species. The authors anticipate this alternative to traditional shielding methods will enable the rapid proliferation of the next generation of compact satellite designs.

Investigation of gamma radiation shielding and antimicrobial properties of PbO-doped ZnO and TiO2 composites

Gamma radiation is utilized in various fields, such as food shelf-life preservation, medicine, and industry. The protection against ionizing radiation, such as gamma radiation, is a crucial matter. Ionizing radiation is harmful to both the environment and living organisms, leading to cellular mutations, organ damage, equipment malfunctions, and other adverse effects. To achieve radiation protection, shielding methods are employed. Materials that prevent bacterial growth and contamination should also be developed in all areas. In our study, glass substrates were coated using the rotational coating method. In this study, the antimicrobial and radiation protection properties of glass coatings prepared with ZnPb (50% ZnO + 50% PbO) and TiPb (50% TiO2 + 50% PbO) ratios were investigated. For radiation protection properties, mass attenuation coefficient (MAC) values were calculated using the Geant4-GATE and XCOM simulations, and the results were compared with the experimental data. Calculations were performed at 511, 662, 1173, 1274, and 1332 keV energy levels. A colony counting method was employed to determine the antibacterial effectiveness of Pb-doped TiO2 and ZnO. The antibacterial efficacy of Pb-doped TiO2 and ZnO films was tested against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) bacteria. It was found that these films were effective only against Staphylococcus aureus bacteria. The antimicrobial efficiency of the nanocomposites was evaluated against various bacterial strains, highlighting significant inhibitory properties, particularly for TiO2 and ZnO nanocomposites against S. aureus. This emphasizes their potential as antimicrobial agents.

Dysprosium-enriched polymer nanocomposites: Assessing radiation shielding and optical properties

This paper includes a comprehensive analysis of the radiation shielding, optical properties, and structural makeup of polymer composites that contain Dy2O3 additions. XRD-pattern investigates the effect of loading Dy2O3 content on PS, with the average crystallite size of Dy2O3 decreases from 39 nm to 30 nm as Dy2O3 increases from 2.5 to 7.5 wt% in the PS matrix. The optical properties of the nanocomposites showed that with the increase in the Dy2O3 content, the transmittance, as well as the direct and indirect band gap, decreased. The EgIndirect bandgap decreased from 3.1 to 2.75 eV with a Dy2O3 increase from 0 to 7.5 wt%, while the Egdirect Bandgap reduced from 4.6 to 4.35 eV. While the Urbach energy Eu and the refractive index increase, Eu rises from 0.48 to 0.60 e V, and n improves from 1.4 to 1.78 from 0 to 7.5 wt%. In order to conduct an accurate analysis of the gamma-ray attenuation capabilities of the selected new polymer composites, these composites were manufactured with varying proportions of the additive components. With the assistance of a Na(Tl) detector, experimental assessments were carried out on the gamma rays throughout a broad spectrum of photon energies, ranging from 81 keV up to 1416 keV. The sample encased in PS/Dy7.5 demonstrates excellent radiation attenuation, and it is important to note that this novel polymer shielding material does not include any hazardous components.

Multifunctional polyimide/boron nitride nanosheet/Ti3C2Tx MXene composite film with three-dimensional conductive network for integrated thermal conductive, electromagnetic interference shielding, and Joule heating performances

With the demand for further miniaturization and higher frequency operation of electronic devices, polymer films with high thermal conductivity and electromagnetic interference (EMI) shielding effectiveness (SE) are urgently required. Herein, polyimide (PI)/boron nitride nanosheets (BNNS) aerogels with oriented porous structure are fabricated by unidirectional-freezing and freeze-drying methods. Subsequently, hierarchical PI/BNNS/Ti3C2Tx composite films with consecutively electrically and thermally conductive networks are successfully prepared via a unidirectional PI/BNNS aerogels-assisted immersion and hot-pressing strategy. Owing to the three-dimensional conductive dual networks of BNNS and Ti3C2Tx, the composite film exhibits excellent thermal conductivity with the maximum in-plane value of 4.73 W/(m·K), increased by 456 % compared to pure PI film. Moreover, the conductive network of Ti3C2Tx is conducive to the excellent EMI shielding performance, endowing the PI/BNNS/Ti3C2Tx composite film with an outstanding EMI SE value of 49.2 dB at 8.2 GHz with a low MXene content of 6 wt% and thickness of 300 μm. Furthermore, the composite film shows the superior Joule heating performance with fast thermal response and sufficient reliability. Therefore, the resulting composite film exhibits excellent thermal conductive, EMI shielding and Joule heating performance, which enables the potential application of multifunctional composites for thermal management and EMI shielding.

Nickel-Fe3O4@Graphene coated lightweight carbonized wood for efficient electromagnetic interference shielding

The miniaturization and integration of electronic equipment promote electromagnetic effect radiation pollution more and more serious. The lightweight, renewable electromagnetic interference (EMI) shielding materials is urgently needed. This study developed a high temperature carbonization, Fe3O4@Graphene impregnation, and electroless Ni technique to construct a carbonized wood composite with strong EMI shielding performance using sustainable natural wood as the raw material. The Fe3O4@Graphene is distributed throughout the carbonized wood to provide the conductivity and magnetism of the reinforced composite material, and provide more interfaces to increase the dielectric loss and magnetic loss, thereby exhibiting excellent EMI shielding performance. The results show that at low thickness (2 mm) and ultra-low density (0.284 g/cm3), the CWN-7 composite exhibits excellent EMI shielding effectiveness of up to 84.2 dB in the whole X-band (8.2–12.4 GHz). At the same time, it has extraordinary compressive strength and good thermal insulation performance. This study offers a different method for creating composite multifunctional electromagnetic shields out of carbonized green wood.

Biobased, recyclable, and multi-functional high-performance composites for electromagnetic interference shielding

High-performance fiber-reinforced thermoset composites (FRTCs) are highly demanded in modern society but are challenged because they depend on nonrenewable fossil-based feedstocks, are hard to recycle after service, and lack advanced functions. Here, we report a methodology to fabricate sustainable, recyclable, high-performance, and multifunctional FRTCs from renewable feedstocks such as vanillin, glycerol triglycidyl ether, 1,10-diaminodecane, and basalt fiber. We designed a mussel-inspired approach to prepare high conductive basalt fiber (CBF), and combined the CBF with a fully biobased covalent adaptable network (CAN) based on dynamic imine bonds to produce the composites i.e., CAN/CBF laminar composites through a solvent-free method. The CAN/CBF composites showed highly reinforced mechanical properties and multiple functionalities including electromagnetic interference shielding, shape memory, and self-adhesion characters through combination in the advantages and functions of both CAN and CBF. Furthermore, we demonstrated that the CAN matrix and the reinforced CBF can be recycled separately and can be further reformed to the CAN/CBF composites due to the dynamic nature of the CAN matrix. Our study thus provides an urgently applicable approach for advanced manufacturing toward the green and circular advanced composites economy.