Fabrication of carbonized spent coffee grounds/graphene nanoplates/cyanate ester composites for superior and highly absorbed electromagnetic interference shielding performance

Guo, Zhengzheng; Ren, Penggang; Zhang, Zengping; Dai, Zhong; Lu, Zhenxia; Jin, Yanling; Ren, Fangfang

doi:10.1016/j.jmst.2021.05.082

Cited by 45 publications

(18 citation statements)

References 48 publications

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“…For that reason, the SE R and SE A are mostly used to describe the EMI shielding mechanism of a certain shield. 5,26,36 Nevertheless, according to the power coefficients, it is confirmed that the rGO prepared in this work is a reflectiondominant EMI shielding foil.…”

Section: Electrical Conductivity and Emi Shieldingsupporting

confidence: 56%

“…Such coefficients are quantitative characteristics of the power balance, whereas SE T is a relative quantity and independent of the absolute power coefficients. For that reason, the SE R and SE A are mostly used to describe the EMI shielding mechanism of a certain shield. ,, Nevertheless, according to the power coefficients, it is confirmed that the rGO prepared in this work is a reflection-dominant EMI shielding foil.…”

Section: Results and Discussionmentioning

confidence: 72%

“…It is thus suggested that the EM waves, that are not reflected, pass through the surface of the rGO foil, and once they face the several graphene interfaces of the expanded architecture, they will be continuously reflected and transmitted until total absorption of the EM waves. Moreover, abundant interfaces in the conductive network act as interfacial polarization sites that enhance dielectric losses, and the impedance mismatch between air present in the expanded architecture and graphene interfaces benefits dipole polarization losses and scattering, and thus, the EM waves are attenuated by microwave absorption. ,, This allows us to conclude that the restored conductive network and the increase in thickness due to the expansion of the graphene architecture, both consequent factors of the thermal reduction process, yielded the EMI shielding properties of the rGO film.…”

Section: Results and Discussionmentioning

confidence: 92%

“…However, bearing in mind that the EMI SE of certain materials results from the combination of reflection, absorption, and multiple internal reflections contributions, it is worth determining the power ( A , R , and T ) coefficients to evaluate the real capability of the rGO foil to reflect, absorb, and transmit EM waves. , The R , T , and A coefficients were determined from the experimental S 11 and S 21 parameters and according to eqs –. The values of R = 0.96 and A = 0.04 at 12.4 GHz (Table S5) indicate a reflection-dominant shielding mechanism in rGO foil due to an impedance mismatch between the rGO foil and free space because of its high electrical conductivity.…”

Section: Results and Discussionmentioning

confidence: 99%

“…13,17 As an EMI shielding material, interestingly, few studies have reported on the EMI shielding properties of pure graphene or rGO films with 100 wt % graphene with the minimum value of EMI SE for practical applications (20−40 dB). 16,25,26 An ultrathin flexible graphene film with an EMI SE of 73.7 dB was recently reported, 27 the best result so far, but its preparation includes the mechanical compression of four layers of porous graphene films, after their thermal reduction, to achieve such a performance. As such, with our work, we intend to demonstrate that with a single step of reduction of GO, it is possible to obtain an rGO freestanding film with an exceptional EMI shielding performance, and no additional procedures consisting of mechanical compression, 28,29 chemical strategies like etching 30 or doping, 31,32 or metal-coating 33 are needed.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Electromagnetic Interference Shielding by Reduced Graphene Oxide Foils

Oliveira

Bouša

Sofer

et al. 2022

ACS Appl. Nano Mater.

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The pursuit of materials to avoid problems associated with electromagnetic pollution has become a relevant research topic. Here, we report the exceptional electromagnetic interference (EMI) shielding performance of freestanding reduced graphene oxide (rGO) foil produced by thermal reduction of graphene oxide (GO). The rGO foil with a thickness of 93.1 ± 12.4 μm reaches an efficient EMI shielding effectiveness (SE) value of 61.6 dB at 12.4 GHz. The excellent performance of the rGO foil is attributed to the thermal reduction of the GO foil, which restores the electrically conductive network, resulting in the electrical conductivity of 1.17 × 104 S m–1. To obtain a more complete profile of the EMI shielding performance of the rGO foil, measurements are performed in G- and C-bands, thus becoming the first study on the EMI shielding performance of an rGO film on a broad frequency range beyond the so-called X-band. The material sustains an EMI shielding efficiency higher than 99.999% over the frequency bands investigated, greatly desired in a wide range of commercial applications in this field.

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Section: Electrical Conductivity and Emi Shieldingsupporting

confidence: 56%

Section: Results and Discussionmentioning

confidence: 72%

Section: Results and Discussionmentioning

confidence: 92%

Section: Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Electromagnetic Interference Shielding by Reduced Graphene Oxide Foils

Oliveira

Bouša

Sofer

et al. 2022

ACS Appl. Nano Mater.

View full text Add to dashboard Cite

show abstract

Design of 3D graphene‐Ni microsphere based polymeric composites for highly efficient and absorption‐dominated electromagnetic interference shielding performance

Qiu,

Ran,

Sun

et al. 2023

Polymer Composites

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The development of polymeric composites that possess both exceptional electromagnetic interference shielding effectiveness (EMI SE) and high absorption capacity has always been appealing, yet it continues to pose a significant challenge. To this end, we disclose a hollow and spherical shielding unit that could achieve “absorption‐reflection‐attenuation” process for incident electromagnetic (EM) wave, which was fabricated through decorating Ni nanoparticles onto rGO hollow microspheres by virtue of Pickering emulsification method followed by thermal annealing. With integrated magnetic and electric parts, the consequent shielding composite by assembling these microspheres into PDMS displayed not only a favorable EMI SE of 44 dB across the entire x‐band, but also significantly improved absorption performance that has exceeded 95% of the total SE. Moreover, the power coefficient of absorption (A) is up to 0.73 at the pyrolysis temperature of 550°C. Such admirable performance is mainly attributed to the synergistic effect of conductive rGO walls, magnetic Ni nanoparticles, as well as the unique spherical architecture, which has enabled more efficient capture and attenuation of EM waves. Herein, this research has highlighted the development of polymeric composites for high‐performance EMI shielding applications.Highlights Reflection‐absorption‐integrated shielding compartment was designed. Decorating magnetic Ni nanoparticles onto rGO hollow microspheres. High EMI SE with enhanced absorption ability was acquired. Unique structure generating synergistic effect on EMI shielding

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Synchronously improved toughness and dielectric properties of cyanate ester resins via modification with biobased poly(N‐phenylmaleimide‐co‐limonene)

Shen,

Chen,

Wang

et al. 2024

Journal of Polymer Science

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High‐performance cyanate ester (CE) resins have attracted intensive interests due to low‐k and heat resistant properties. However, the extreme high curing temperature and inherent brittleness severely limit their practical application. Herein, novel biobased poly(N‐phenylmaleimide‐co‐limonene) (PML) microspheres were specially designed and synthesized by self‐stabilized precipitation polymerization, which could simultaneously serve as effective curing agents and toughening modifiers for 2,2‐bis(4‐cyanatophenyl) propane (BADCy). The high density of unreacted endocyclic vinyl groups in PML could effectively react with BADCy, leading to lower curing temperature and good interfacial compatibility. Benefitting from both the weakly polarizable flexible chains and the highly crosslinked semi‐interpenetrating network formed during the curing process, BADCy/PML resins exhibited highly enhanced toughness and reduced dielectric constant (ε). Specifically, the BADCy/PML resins showed minimum values of ε and dielectric loss of 2.61 and 0.0032 at 106 Hz, much lower than BADCy resins (2.88, 0.0052). More importantly, a maximum impact strength of 15.6 kJ/m2 was achieved at 10 wt% loading of PML, which was 86% higher than BADCy resin. In summary, this work developed a novel strategy to simultaneously improve toughness and dielectric properties of CE resins using bio‐based PML copolymer, which have great potential in the fields of electronics and information technology.

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Fabrication of carbonized spent coffee grounds/graphene nanoplates/cyanate ester composites for superior and highly absorbed electromagnetic interference shielding performance

Cited by 45 publications

References 48 publications

Electromagnetic Interference Shielding by Reduced Graphene Oxide Foils

Electromagnetic Interference Shielding by Reduced Graphene Oxide Foils

Design of 3D graphene‐Ni microsphere based polymeric composites for highly efficient and absorption‐dominated electromagnetic interference shielding performance

Synchronously improved toughness and dielectric properties of cyanate ester resins via modification with biobased poly(N‐phenylmaleimide‐co‐limonene)

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