Lightweight, multifunctional microcellular PMMA/Fe3O4@MWCNTs nanocomposite foams with efficient electromagnetic interference shielding
TL;DR: In this article, a lightweight and multifunctional PMMA/Fe 3 O 4 @MWCNTs composite foams with density of 0.22 and 0.38 g/cm 3 were fabricated by supercritical carbon dioxide (ScCO 2 ) foaming process.
Abstract: Lightweight and multifunctional PMMA/Fe 3 O 4 @MWCNTs composite foams with density of 0.22–0.38 g/cm 3 were fabricated by supercritical carbon dioxide (ScCO 2 ) foaming process. Benefitting from the existence of microcellular structure and the Fe 3 O 4 @MWCNTs hybrids, the specific Electromagnetic interference shielding effectiveness (EMI SE) of obtained PMMA/Fe 3 O 4 @MWCNTs foams was significantly enhanced. The resulting foams with hybrids loading of 7 wt% displayed excellent specific EMI SE of 50 dB/(g/cm 3 ) over the X-band. Furthermore, the EMI shielding mechanisms of the porous materials were discussed and it suggested that the dominant contribution to EMI SE was absorption. Meanwhile, the high-strength composite foams also exhibited superparamagnetic behavior and low thermal conductivity of 0.080–0.142 W/(m k). In this work, we provide a feasible way to produce lightweight and multifunctional PMMA/Fe 3 O 4 @MWCNTs foams with superior EMI shielding performance to apply in the electronics and aerospace industries.
Citations
More filters
TL;DR: In this article, a review of the recent advances in carbon-based polymer nanocomposites for electromagnetic interference (EMI) shielding is presented and related to structure and processing, focusing on the effects of nanoparticle aspect ratio and possible functionalization, dispersion and alignment during processing, as well as the use of nanohybrids and 3D reinforcements.
405 citations
TL;DR: In this paper, the authors reviewed conductive polymer composites (CPC) with multiple interfaces which have demonstrated to improve EMI SE, including foamed/porous, segregated, multi-component, multilayered/sandwiched and prefabricated conductive networks.
318 citations
TL;DR: In this paper, a review of the approaches related to porous high EMI shielding composite materials that have very low density values is presented, focusing on porous materials for electromagnetic interference (EMI) shielding.
Abstract: Lightweight porous materials for electromagnetic interference (EMI) shielding applications are reviewed. EMI shielding refers to the capability of a material to protect from electromagnetic fields (EMFs) generated by electronic devices. Traditionally conducting metals are used in EMI shielding applications, which are slowly being replaced by conducting polymer based shields. This review is narrowly focused on understanding the approaches related to porous high EMI shielding composite materials that have very low density values. While metallic fillers can increase the EMI shielding capabilities of polymers, they also increase the weight, which can be offset by inducing the porosity in the matrix. Porosity is found to be effective in providing higher shielding effectiveness at low filler volume fraction due to concentrating the filler in the solid polymers. However, use of gas porosity results in composites with low mechanical properties. This problem can be alleviated to some extent by reinforcing polymer foams with lightweight conductivefillers such as carbon nanofibers (CNFs), carbon nanotubes (CNTs) and graphene. But the properties of pores such aspore size and distribution cannot be effectively controlled in such cases. Syntactic foams containing hollow particle fillers seem to be the best combination of EMI shielding capabilities and mechanical properties. These composites can be either filled with a second phase conducting filler, or hollow particles can be coated with a conducting layer, or hollow particles made of conducting materials can be used as fillers. The hollow particle wall thickness and volume fractions can be optimized to obtain the desired combination of properties in syntactic foams to enable their multifunctional applications.
310 citations
TL;DR: In this paper, two different dimensional nanofillers of MWCNTs and GNPs were used as bifillers to explore their synergistic effect on the final mechanical and electrical properties.
227 citations
TL;DR: The as-prepared CNT/PI foam presents higher EMI SE than 35 dB even after being subjected to the flame of alcohol burner, which indicates a certain potential application in the fields of aerospace as a high-efficient and lightweight EMI shielding material.
Abstract: Excellent electromagnetic interference (EMI) shielding ability, light weight, and good heat resistance are highly required for practical applications of EMI shielding materials, such as in areas of aerospace, aircraft, and automobiles. Herein, a lightweight and robust carbon nanotube (CNT)/polyimide (PI) foam was developed for efficient and heat-resistant EMI shielding. Thanks to poly(vinyl pyrrolidone) (PVP) as a surfactant that not only promotes the uniform dispersion of CNTs to form perfect CNT conductive networks but also can be removed in situ during the polymerization process, the density of resultant CNT/PI foam is only 32.1 mg·cm-3, and the EMI shielding effectiveness (EMI SE) is up to 41.1 dB, which represents one of the highest EMI SE values compared to previously reported polymer-based foams. The CNT/PI foam also achieves the absorption coefficient (A) of up to 82.3%, which is very impressive in CNT/polymer foams at comparable EMI SE levels. The PI matrix endows the foam with excellent heat resistance. The as-prepared CNT/PI foam presents a higher EMI SE than 35 dB even after being subjected to the flame of an alcohol burner. Moreover, the compressive strength and compressive modulus are up to 240.9 and 323.9 kPa. These results indicate its certain application potential in the harsh requirement of aeronautics and aerospace industries as a highly efficient and lightweight EMI shielding material.
180 citations
References
More filters
TL;DR: Carbon materials for electromagnetic interference (EMI) shielding are reviewed in this article, including composite materials, colloidal graphite and flexible graphite, and they include carbon filaments of submicron diameter.
1,676 citations
TL;DR: In this article, the electromagnetic interference (EMI) shielding mechanisms of multi-walled carbon nanotube (MWCNT)/polymer composites were analyzed experimentally and theoretically.
1,222 citations
TL;DR: The electromagnetic interference (EMI) shielding effectiveness measurements indicated that a novel carbon nanotube-polystyrene foam composite can be used as very effective, lightweight shielding materials.
Abstract: A novel carbon nanotube-polystyrene foam composite has been fabricated successfully. The electromagnetic interference (EMI) shielding effectiveness measurements indicated that such foam composites can be used as very effective, lightweight shielding materials. The correlation between the shielding effectiveness and electrical conductivity and the EMI shielding mechanism of such foam composites are also discussed.
1,152 citations
TL;DR: The results indicate that single-walled carbon nanotube-polymer composites can be used as effective lightweight EMI shielding materials and are found to correlate with the dc conductivity.
Abstract: Single-walled carbon nanotube (SWNT)−polymer composites have been fabricated to evaluate the electromagnetic interference (EMI) shielding effectiveness (SE) of SWNTs. Our results indicate that SWNTs can be used as effective lightweight EMI shielding materials. Composites with greater than 20 dB shielding efficiency were obtained easily. EMI SE was tested in the frequency range of 10 MHz to 1.5 GHz, and the highest EMI shielding efficiency (SE) was obtained for 15 wt % SWNT, reaching 49 dB at 10 MHz and exhibiting 15−20 dB in the 500 MHz to 1.5 GHz range. The EMI SE was found to correlate with the dc conductivity, and this frequency range is found to be dominated by reflection. The effects of SWNT wall defects and aspect ratio on the EMI SE were also studied.
1,148 citations
TL;DR: Self-aligned in situ reduced graphene oxide (rGO)/polymer nanocomposites with the engineered structure and properties present high performance electromagnetic interference shielding with a remarkable shilding efficiency of 38 dB.
Abstract: Nanocomposites that contain reinforcements with preferred orientation have attracted significant attention because of their promising applications in a wide range of multifunctional fields. Many efforts have recently been focused on developing facile methods for preparing aligned graphene sheets in solvents and polymers because of their fascinating properties including liquid crystallinity and highly anisotropic characteristics. Self-aligned in situ reduced graphene oxide (rGO)/polymer nanocomposites are prepared using an all aqueous casting method. A remarkably low percolation threshold of 0.12 vol% is achieved in the rGO/epoxy system owing to the uniformly dispersed, monolayer graphene sheets with extremely high aspect ratios (>30000). The self-alignment into a layered structure at above a critical filler content induces a unique anisotropy in electrical and mechanical properties due to the preferential formation of conductive and reinforcing networks along the alignment direction. Accompanied by the anisotropic electrical conductivities are exceptionally high dielectric constants of over 14000 with 3 wt% of rGO at 1 kHz due to the charge accumulation at the highly-aligned conductive filler/insulating polymer interface according to the Maxwell-Wagner-Sillars polarization principle. The highly dielectric rGO/epoxy nanocomposites with the engineered structure and properties present high performance electromagnetic interference shielding with a remarkable shilding efficiency of 38 dB.
1,011 citations