The development of high-performance shielding materials against electromagnetic pollution requires mobile charge carriers and magnetic dipoles. Herein, we meet the challenge by building a ...three-dimensional (3D) nanostructure consisting of chemically modified graphene/Fe
3
O
4
(GF) incorporated polyaniline. Intercalated GF was synthesized by the
in situ
generation of Fe
3
O
4
nanoparticles in a graphene oxide suspension followed by hydrazine reduction, and further
in situ
polymerization with aniline to form a polyaniline composite. Spectroscopic analysis demonstrates that the presence of GF hybrid structures facilitates strong polarization due to the formation of a solid-state charge-transfer complex between graphene and polyaniline. This provides proper impedance matching and higher dipole interaction, which leads to the high microwave absorption properties. The higher dielectric loss (
′′ = 30) and magnetic loss (
μ
′′ = 0.2) contribute to the microwave absorption value of 26 dB (>99.7% attenuation), which was found to depend on the concentration of GF in the polyaniline matrix. Moreover, the interactions between Fe
3
O
4
, graphene and polyaniline are responsible for superior material characteristics, such as excellent environmental (chemical and thermal) degradation stability and good electric conductivity (as high as 260 S m
−1
).
Graphene/Fe
3
O
4
incorporated polyaniline has been synthesized for EMI shielding which contributes to high microwave absorption value of 26 dB.
•Lightweight tiles were inventively fabricated by simple and novel process.•Utilization of waste plastic bags as matrix reinforced with fly ash as filler.•The obtained tiles demonstrates good thermal ...stability and tensile strength of 9.68 MPa.•Composites tiles possess linear burning rate of 4.36 mm/min.•Resistance to acids and bases with negligible water absorption.
This paper is focused on finding effective alternative for disposal of waste plastic bags by designing tiles with better mechanical strength, reduced flammability level, resistant against strong acids and bases and organic solvents, so that tiles can be used for designing structures for paver tiles for societal usage. In recent years the plastic consumption has increased manifolds leading to accumulation of plastic waste in large amount. Waste plastic bags being non-biodegradable and its extreme durability make its disposal process difficult. Plastic solid waste (PSW) present challenges and opportunities to the societies regardless of their technological advances and sustainability awareness. Traditional technologies for waste plastic disposal have failed to cope up with the increased generation of plastic waste. Also, the disposal of fly ash, waste by-product generated by combustion of coal in thermal power plants, is a serious problem both in terms of land use and environmental pollution. In this study, waste plastic matrix reinforced with fly ash (FA) and a flame retardant at different loadings (wt %) 5, 10, 15, 20 using twin screw extruder were molded into composite tiles and their characteristics were evaluated. Effect of different filler loading on waste plastic matrix was investigated. Composite (LFTP3) having appropriate ratios of fly ash and flame retardant showed reduced flammability with linear burning rate of 4.36 mm/minute and improved tensile strength of 9.68 MPa. Morphological and structural properties of all the composites were also investigated along with their flammability, resistance to different acids and bases and organic solvents, water absorption and mechanical strength.
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•An attempt to find out application of Barium Ferrite & Graphite integrated with Polyaniline composite for electromagnetic Radiation Shielding.•Using and testing of composite ...materials shielding effectiveness instead of the other widely used materials.•Synthesis and Characterization of materials for its application as a shielding material.•Dielectric and Electromagnetic shielding behavior study of PANI/EG/BaFe12O19 composite.
Barium ferrite was incorporated into polyaniline matrix along with expanded graphite (EG) in order that the resultant conductive composite can be used for electromagnetic shielding. The different properties like complex permittivity (ε′′), permeability (μ′′), and effectiveness of shielding have been studied by vector network analyzer using theoretical enumeration given in Weir and Nicholson–Ross algorithms. The microwave absorption characteristic of the composites have been calculated in the X-band (8.2–12.4GHz) frequency range which shows a shielding effectiveness up-to 37.1dB, which strongly depends on dielectric loss.
Multi-walled carbon nanotube (MWCNT)/portland cement(PC) composites have been fabricated to evaluate their electromagnetic interference (EMI) shielding effectiveness (SE). The results show that they ...can be used for the shielding of EMI in the microwave range. The incorporation of 15wt.% MWCNTs in the PC matrix produces a SE more than 27dB in X-band (8.2–12.4GHz), and this SE is found to be dominated by absorption. Furthermore, the structural analysis, surface morphology and surface interaction of MWCNTs with PC matrix have been explored using XRD, SEM and X-ray photoelectron spectroscopy technique.
Lightweight and easily foldable with high conductivity, multiwalled carbon nanotube (MWCNT)-based mesocarbon microbead (MCMB) composite paper is prepared using a simple, efficient, and cost-effective ...strategy. The developed lightweight and conductive composite paper have been reported for the first time as an efficient electromagnetic interference (EMI) shielding material in X-band frequency region having a low density of 0.26 g/cm3. The investigation revealed that composite paper shows an excellent absorption dominated EMI shielding effectiveness (SE) of −31 to −56 dB at 0.15–0.6 mm thickness, respectively. Specific EMI-SE of as high as −215 dB cm3/g exceeds the best values of metal and other low-density carbon-based composites. Additionally, lightweight and easily foldable ability of this composite paper will help in providing stable EMI shielding values even after constant bending. Such intriguing performances open the framework to designing a lightweight and easily foldable composite paper as promising EMI shielding material, especially in next-generation devices and for defense industries.
There is an increased interest in the development of high performance microwave shielding materials against electromagnetic pollution in recent years. Barium ferrite decorated reduced graphene oxide ...(BaFe12O19@RGO) nanocomposite was synthesized by a high energy ball milling technique and its electromagnetic properties were investigated in the frequency range of 12.4-18 GHz (Ku band). The results showed that barium ferrite (BaFe12O19) nanoparticles with an average particle size of 20-30 nm were well distributed and firmly anchored onto the surface of the reduced graphene oxide sheets. The obtained nanocomposite exhibited a saturation magnetization of 18.1 emu g(-1) at room temperature. The presence of BaFe12O19 nanoparticles in the nanocomposite enhances the space charge polarization, natural resonance, multiple scattering and the effective anisotropy energy leading to a high electromagnetic interference shielding effectiveness of 32 dB (∼99.9% attenuation) at a critical thickness of 3 mm. The results suggested that the as-prepared BaFe12O19@RGO nanocomposite showed great potential as an effective candidate for a new type of microwave absorbing material.
Composite sheets consisting of phenolic resin filled with a mixture of reduced graphene oxide (RGO), γ-Fe2O3 and carbon fibers have been produced by compression molding. Its electrical conductivity ...lies in the range 0.48–171.21S/cm. Transmission and scanning electron microscopy observations confirm the presence of nano particles of γ-Fe2O3 (∼9.8nm) and carbon fiber (∼1mm) which gives flexural strength to composite sheets. Thermogravimetric analysis show that the thermal stability of the sheets depend upon the amount of RGO and phenol resin in the composite. Complex parameters, i.e., permittivity (ε*=ε′−iε″) and permeability (μ*=μ′−iμ″) of RGO/γ-Fe2O3/carbon fiber have been calculated from experimental scattering parameters (S11 and S21) using theoretical calculations given in Nicholson−Ross and Weir algorithms. The microwave absorption properties of the sheets have been studied in the 8.2–12.4GHz (X-Band) frequency range. The maximum shielding effectiveness observed is 45.26dB, which strongly depends on dielectric loss and volume fraction of γ-Fe2O3 in RGO matrix.
Expanded graphite (EG) was incorporated into fly ash matrix along with nanoferrite γ-Fe2O3 particles so that the resultant conductive fly ash composite can be used for electromagnetic shielding in ...microwave range (X-band). Transmission electron microscopy (TEM) images of EG/γ-Fe2O3/fly ash hybrid structure show that fly ash particle (0.87μm) is wrapped by sheets of expanded graphite containing the γ-Fe2O3 particles (15–25nm). Display omitted
► By changing the wt% of expanded graphite (EG), γ-Fe2O3 and fly ash the composites have been formed. ► Fly ash particle (0.87μm) is covered by sheets of EG containing the γ-Fe2O3 particles (15–25nm). ► EG/γ-Fe2O3 /fly ash composites shows a shielding effectiveness ∼ 90 dB in the X-band frequency range.
Expanded graphite (EG) was incorporated into fly ash matrix along with nanoferrite γ-Fe2O3 particles so that the resultant conductive fly ash composite can be used for electromagnetic shielding in microwave range. Conductivity of composites lies in the range 0.34–32.86S/cm. TEM images show that fly ash particle (0.87μm) is covered by sheets of EG containing the magnetic nanoparticles. Complex parameters have been calculated from experimental scattering parameters (S11 and S21) using theoretical calculations given in Nicholson–Ross and Weir algorithms. The microwave absorption properties of the composites have been studied in the 8.2–12.4GHz (X-band) frequency range which shows a shielding effectiveness up-to 90dB, which strongly depends on dielectric loss and weight fraction of fly ash and γ-Fe2O3 in EG matrix.
Insights into advances in portable and flexible electronic devices can be gained from the integration of magnetic nanoparticles with light weight and flexible conductive supports, especially in cases ...where the thickness of the material is challenging for future electromagnetic interference shielding applications. Here we report the fabrication of flexible shielding materials made up of Fe
3
O
4
nanoparticles incorporated mesocarbon microbeads and multiwalled carbon nanotubes (MCMBs/MWCNTs) composite paper for efficient electromagnetic interference (EMI) shielding in the X-band frequency region (8.2-12.4 GHz). The incorporation of Fe
3
O
4
nanoparticles in the MCMBs/MWCNTs composite paper significantly increases its interfacial polarization and anisotropy energy, which leads to an excellent absorption dominated EMI shielding effectiveness (SE) of −80 dB at 0.5 mm thickness. The composite paper also exhibits improved magnetic properties coupled with enhanced dielectric properties that increase with increasing concentration of Fe
3
O
4
nanoparticles. Our measurements have provided a regime for designing conductive networks with advantages of light weight and flexibility, with promising EMI shielding applications.
A hybrid three phase system containing MCMBs/MWCNTs/Fe
3
O
4
in the form of a highly flexible and light weight composite paper is fabricated by simple cost effective strategies and is promising EMI shielding applications.
Highly conducting polyaniline (PANI)–multi-walled carbon nanotube (MWCNT) nanocomposites were prepared by in situ polymerization. The FTIR and XRD show systematic shifting of the characteristic bands ...and peaks of PANI, with the increase in MWCNT phase, suggesting significant interaction between the phases. The SEM and TEM pictures show thick and uniform coating of PANI over surface of individual MWCNT. Based on observed morphological features in SEM, the probable formation mechanism of these composites has been proposed. The electrical conductivity of PANI–MWCNT composite (19.7
S
cm
−1) was even better than MWCNT (19.1
S
cm
−1) or PANI (2.0
S
cm
−1). This can be ascribed to the synergistic effect of two complementing phases (i.e. PANI and MWCNT). The absorption dominated total shielding effectiveness (SE) of −27.5 to −39.2
dB of these composites indicates the usefulness of these materials for microwave shielding in the Ku-band (12.4–18.0
GHz). These PANI coated MWCNTs with large aspect ratio are also proposed as hybrid conductive fillers in various thermoplastic matrices, for making structurally strong microwave shields.
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