Ultra-porous and lightweight microwave absorber based on epoxy foam loaded with long carbon fibers

Breiss, Hanadi; Assal, Aicha El; Benzerga, Ratiba; Sharaiha, Ala; Jrad, Akil; Harmouch, Ali

doi:10.1016/j.materresbull.2020.111188

Cited by 22 publications

(7 citation statements)

References 42 publications

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“…For RAM based on thermoplastic matrices, the following processing methods are widely used: (i) molding under pressure in a press or autoclave [ 87 ], (ii) extrusion methods [ 88 ], and (iii) additive technologies [ 89 , 90 ]. Such methods as pouring compositions [ 91 ], pressing [ 92 , 93 ] and autoclave molding [ 94 ], paint and varnish application methods [ 95 , 96 ], technologies for manufacturing porous structures [ 97 ], and impregnation technologies [ 98 , 99 ] are used for production the RAMs based on fiber-reinforced polymer composites. In some cases, to expand the operating radio frequency range and ensure a set of requirements for performance characteristics (physical, mechanical, thermal, resistance to external factors, etc.…”

Section: Radio-absorbing Materials and Technologies For Their Productionmentioning

confidence: 99%

Radio-Absorbing Materials Based on Polymer Composites and Their Application to Solving the Problems of Electromagnetic Compatibility

et al. 2022

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Recently, designers of electronic equipment have paid special attention to the issue of electromagnetic compatibility (EMC) of devices with their own components and assemblies. This is due to the high sensitivity of semiconductor microcircuits to electromagnetic interference. This interference can be caused either by natural phenomena, such as lightning strikes, or by technical processes, such as transients in circuits during fast periodic or random switching. Either way, interference implies a sudden change in voltage or current in a circuit, which is undesirable, whether it propagates along a cable or is transmitted as an electromagnetic wave. The purpose of this article is to review the works devoted to the development, creation, and investigation of modern polymeric nanocomposite materials used for shielding electromagnetic radiation and their effective application for solving problems of electromagnetic compatibility. Additionally, the approach to design EMI shielding complex media with predetermined parameters based on investigation of various properties of possible components is shown. In the review, all polymer composites are classified according to the type of filler. The issues of the interaction of a polymer with conductive fillers, the influence of the concentration of fillers and their location inside the matrix, and the structure of the nanocomposite on the mechanisms of electromagnetic interaction are considered. Particular attention is paid to a new generation of nanocomposite materials with widely adjustable electrical and magnetic properties. A wide class of modern filled polymeric materials with dielectric and magneto-dielectric losses is considered. These materials make it possible to create effective absorbers of electromagnetic waves that provide a low level of reflection coefficient in the microwave range. The model mechanisms for shielding electromagnetic radiation are considered in the paper. A detailed review of the electro-physical properties of polymer nanocomposites is provided. Multilayer electrodynamic media containing combinations of layers of filled polymer composite materials with nanoparticles of different compositions and manufactured using a single technology will make it possible to create electrodynamic media and coatings with the required electro-physical characteristics of absorption, transmission, and reflection. Within the framework of the two-layer coating model, the difference in the effects of the interaction of electromagnetic radiation with conductive layers located on a dielectric and metal substrate is demonstrated. It is shown that in order to achieve optimal (maximum) values of reflection and absorption of electromagnetic radiation in the appropriate frequency range, it is necessary to fit the appropriate layer thicknesses, specific conductivity, and permittivity. Such approach allows designers to create new shielding materials that can effectively vary the shielding, absorbing, and matching characteristics of coatings over a wide frequency band. In general, it can be said that the development of innovative polymer composite materials for shielding electronic devices from electromagnetic interference and excessive electromagnetic background is still an important task. Its solution will ensure the safe and uninterrupted operation of modern digital electronics and can be used for other applications.

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Section: Radio-absorbing Materials and Technologies For Their Productionmentioning

confidence: 99%

Radio-Absorbing Materials Based on Polymer Composites and Their Application to Solving the Problems of Electromagnetic Compatibility

et al. 2022

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“…into thermal energy or other forms of energy. 39,40 According to the propagation process of EMW, the possible schemes to achieve excellent absorption can be discussed as follows: (1) improving the impedance match between MWAM and M.W. so that M.W.…”

Section: Introductionmentioning

confidence: 99%

A review of graphene-based broad bandwidth microwave absorbing textile-based composites in the low-frequency range

Aiqiong

Chen

et al. 2022

Journal of Industrial Textiles

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The range and strength of Electromagnetic Wave loss are increasing with the development of electronic technology in intellectualization and diversification. Extensive research is focused on high-frequency microwave absorbersbut rarely on low-frequency ones. However, the shield of low-frequency microwave interference is bulky and complicated. It is necessary to adopt new structural composites with lightweight, porous, or multi-layer magneto-dielectric synergistic to obtain lighter, thinner, broader bandwidth, and strong absorption absorbers in the low-frequency range. The porous and multi-layer textiles would extend the Microwave (M. W.) transmitting pathway. The prepared M. W. textile-based composites possess broad bandwidth and strong absorption in the low-frequency range when magneto-dielectric synergistic functional particles have embedded in the textiles. This paper reviewed the modified graphene-based absorbers (GBAs), the hybrids combined GBAs with the low-frequency magnetic loss absorbers (LFMLAs), and the textile-based composites added by the complex combined GBAs with LFMLAs (GBAs/LFMLAs). The prepared GBAs/LFMLAs textile-based composites are broad bandwidth, lightweight, small thickness, and strong absorption materials in the low-frequency range. The prepared GBAs/LFMLAs textile-based microwave absorbers (MWAs) may expand the application scope of MWAs and promote their economic benefit. The GBAs/LFMLAs textile-based composites may propose a new strategy of broad bandwidth MWAs in the low-frequency range.

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“…Thermoset foams have become more and more essential in various industry sectors. These foams are used in applications requiring good thermal stability, high flame resistance, burning without drips and excellent solvent resistance, for example, in automotive, electronic, marine, aeronautical and space products [ 1 , 2 , 3 ]. Common thermoset foams are polyurethane, phenolic and epoxy.…”

Section: Introductionmentioning

confidence: 99%

New Insights on Expandability of Pre-Cured Epoxy Using a Solid-State CO2-Foaming Technique

et al. 2021

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Foaming an epoxy is challenging because the process involves the curing reaction of epoxy and hardener (from monomer to oligomer, to a gel and a final three-dimensional crosslinked network) and the loading of gas phase into the epoxy phase to develop the cellular structure. The latter process needs to be carried out at the optimum curing stage of epoxy to avoid cell coalescence and to allow expansion. The environmental concern regarding the usage of chemical blowing agent also limits the development of epoxy foams. To surmount these challenges, this study proposes a solid-state CO2 foaming of epoxy. Firstly, the resin mixture of diglycidylether of bisphenol-A (DGEBA) epoxy and polyamide hardener is pre-cured to achieve various solid-state sheets (preEs) of specific storage moduli. Secondly, these preEs undergo CO2 absorption using an autoclave. Thirdly, CO2 absorbed preEs are allowed to free-foam/expand in a conventional oven at various temperatures; lastly, the epoxy foams are post-cured. PreE has a distinctive behavior once being heated; the storage modulus is reduced and then increases due to further curing. Epoxy foams in a broad range of densities could be fabricated. PreE with a storage modulus of 4 × 104–1.5 × 105 Pa at 30 °C could be foamed to densities of 0.32–0.45 g/cm3. The cell morphologies were revealed to be star polygon shaped, spherical and irregularly shaped. The research proved that the solid-state CO2-foaming technique can be used to fabricate epoxy foams with controlled density.

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Ultra-porous and lightweight microwave absorber based on epoxy foam loaded with long carbon fibers

Cited by 22 publications

References 42 publications

Radio-Absorbing Materials Based on Polymer Composites and Their Application to Solving the Problems of Electromagnetic Compatibility

Radio-Absorbing Materials Based on Polymer Composites and Their Application to Solving the Problems of Electromagnetic Compatibility

A review of graphene-based broad bandwidth microwave absorbing textile-based composites in the low-frequency range

New Insights on Expandability of Pre-Cured Epoxy Using a Solid-State CO2-Foaming Technique

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