Thermally insulating robust carbon composite foams with high EMI shielding from natural cotton

Chithra, A.; Wilson, Praveen; Vijayan, Sujith; Ramanan, Rajeev; Prabhakaran, K.

doi:10.1016/j.jmst.2021.02.064

Cited by 32 publications

(16 citation statements)

References 64 publications

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“…To further evaluate the thermal insulation performance of CG aerogels, we referred to the thermal conductivity and density of the recently reported porous carbon materials. As shown in Figure d and Table S5, the CG aerogels we prepared demonstrated excellent heat insulation performance compared with the data from these studies. − …”

Section: Results and Discussionsupporting

confidence: 54%

Anisotropic and Lightweight Carbon/Graphene Composite Aerogels for Efficient Thermal Insulation and Electromagnetic Interference Shielding

Jiang

Zhao

Zhou

et al. 2022

ACS Appl. Mater. Interfaces

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High-performance and lightweight carbon aerogels (CAs) have attracted considerable attention in various fields such as electrochemistry, catalysis, adsorption, energy storage, and so on. However, finding an environmentally friendly and efficient preparation method and achieving a controllable performance of CAs are still a challenge. Herein, a series of anisotropic carbon/graphene composite aerogels were synthesized by unidirectional freezing of polyamic acid ammonium salt/graphene oxide (PAS/GO) suspension followed by lyophilization, thermal imidization, and carbonization. The prepared aerogels presented a tubular pore structure oriented along the freezing direction. The GO dispersed in the polymer matrix reinforced the skeleton of aerogels, which significantly inhibited the volume shrinkage during the preparation process, thus giving low densities of 0.074–0.185 g cm–3. In addition, the oriented pore structure endowed the composite aerogels with obviously anisotropic heat insulation performance. The radial thermal conductivity was as low as 0.038 W m–1 K–1 at the density of 0.074 g cm–3. When the initial content of GO rose to 20 phr, the resultant aerogels exhibited a high electrical conductivity of about 0.77 S cm–1 in the radial direction and the electromagnetic interference shielding effectiveness (EMI SE) reached 54.6 dB at the same time. Therefore, this study provided a facile and environmentally friendly method to prepare lightweight and anisotropic carbon aerogels.

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Section: Results and Discussionsupporting

confidence: 54%

Anisotropic and Lightweight Carbon/Graphene Composite Aerogels for Efficient Thermal Insulation and Electromagnetic Interference Shielding

Jiang

Zhao

Zhou

et al. 2022

ACS Appl. Mater. Interfaces

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“…The EMI shields work by a combination of reflection and absorption mechanisms. − EMI shielding materials in the porous form are preferred over their dense counterparts as the pores improve the impedance matching leading to the easy penetration of EM waves into the material and enhances the EM absorption due to the availability of more surface. The waves that penetrate the shielding material undergo multiple internal reflections within the pores leading to enhanced absorption. ,, Recently, carbon-based foams are attracting renewed interest as EMI shields over their metallic counterparts because they are lightweight, noncorroding, inexpensive, and easy to fabricate. A typical graph showing the shielding effectiveness as a function of the frequency of a carbon foam produced from vermicelli and a 90 vol % PF solution measured in the X band region of microwave spectra is shown in Figure a.…”

Section: Resultsmentioning

confidence: 99%

“…Carbon foam monoliths are also reported from biomasses such as cotton, paper waste, sawdust, and rice husk by employing a filter-pressing method. 20,21 Solid-state foaming is a relatively new method for the preparation of microcellular polymer foams. 22−25 Unlike the conventional foaming of molten polymers or polymer resins, in solid state foaming, the polymer remains in the solid form throughout the foaming process.…”

Section: Introductionmentioning

confidence: 99%

Carbon Foams by Solid State Foaming of Short Vermicelli Bonded by Phenol-Formaldehyde for Thermal Insulation and Electromagnetic Interference Shielding

Saraswathy

Sharma

Prabhakaran

2023

ACS Appl. Eng. Mater.

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A simple method of production of carbon foams by randomly assembling short vermicelli rods and bonding them using phenol-formaldehyde (PF) followed by foaming in the solid state during carbonization has been reported. The brittle vermicelli becomes ductile in the range of 200−250 °C during carbonization, which facilitates the nucleation and growth of bubbles in the solid state due to the water vapor generated by the -OH condensation of starch. The dense PF coating on the vermicelli surface facilitates the enlargement of cells by restricting the escape of water vapor during the solid state foaming. The dense carbon produced from the PF binds the carbonized vermicelli rods, affording structural integrity and mechanical strength. The foam body consists of open intervermicelli void space and closed cellular pores in the carbonized vermicelli rods. A broad cell size range of 4−142 μm with an average value of 29.2 μm is observed. The density, compressive strength, and thermal conductivity of the carbon foam are modulated in the ranges of 0.30−0.34 g cm −3 , 0.63−1.6 MPa, and 0.162−0.222 W m −1 K −1 , respectively, by changing the PF solution concentration in the range of 50−90 vol %. The carbon foams exhibit absorption-dominated electromagnetic interference shielding with total shielding effectiveness and specific shielding effectiveness in the ranges of 47.5−65.6 dB and 155.2−192.9 dB cm 3 g −1 , respectively, for the X band (8.2−12.4 GHz).

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“…The universal testing machine (GNT100, NCS Testing Technology Co., Ltd., Beijing, China) was used to test the mechanical properties of graphene-modified carbon foam composites. First, the composite materials were cut into small samples with the dimension 10 mm × 10 mm × 10 mm; these samples were compressed between two stainless platens with a loading rate of 0.5 mm/min, which is widely adopted in the compression strength testing of carbon foam [ 32 , 33 ], and then the stress–strain curve of the samples was obtained, as well as the failure load P and the compression section area A. Finally, compression strength σ of these samples was calculated according to the following formula: σ = P/A …”

Section: Methodsmentioning

confidence: 99%

Preparation and Adsorption Properties of Graphene-Modified, Pitch-Based Carbon Foam Composites

Li¹,

Li²,

Deng³

et al. 2022

Polymers

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In view of the good adsorption properties of graphene and carbon foam, they were combined to achieve the optimal matching of microstructures. Taking mesophase pitch as a raw material, pitch-based carbon foam was prepared by the self-foaming method. Graphene gel was prepared as the second phase to composite with the carbon foam matrix; graphene-modified, pitch-based carbon foam composites were finally obtained. Graphene gel was dispersed in the rich pore structure of carbon foam to improve its agglomeration and the porosity, and the active sites of the composite were further increased; the adsorption properties and mechanical properties of the composites were also significantly improved. The microstructure and morphology of the composites were studied by SEM, XRD and Raman spectroscopy; the compressive property and porosity were also tested. Methylene blue (MB) solution was used to simulate a dye solution for the adsorption test, and the influence of the composite properties and MB solution on the adsorption property was studied. Results showed that the compressive strength of the composite was 13.5 MPa, increased by 53.41%, and the porosity was 58.14%, increased by 24.15%, when compared to raw carbon foam. When the mass of the adsorbent was 150 mg, the initial concentration of the MB solution was 5 mg/L, and the pH value of the MB solution was 11; the graphene-modified carbon foam composites showed the best adsorption effect, with an adsorption rate of 96.3% and an adsorption capacity of 144.45 mg/g. Compared with the raw carbon foam, the adsorption rate and adsorption capacity of the composites were increased by 158.18% and 93.50%, respectively.

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Thermally insulating robust carbon composite foams with high EMI shielding from natural cotton

Cited by 32 publications

References 64 publications

Anisotropic and Lightweight Carbon/Graphene Composite Aerogels for Efficient Thermal Insulation and Electromagnetic Interference Shielding

Anisotropic and Lightweight Carbon/Graphene Composite Aerogels for Efficient Thermal Insulation and Electromagnetic Interference Shielding

Carbon Foams by Solid State Foaming of Short Vermicelli Bonded by Phenol-Formaldehyde for Thermal Insulation and Electromagnetic Interference Shielding

Preparation and Adsorption Properties of Graphene-Modified, Pitch-Based Carbon Foam Composites

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