•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.
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.
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.
Blends of polystyrene with polyaniline (PANI) coated multiwalled carbon nanotubes (MWCNTs) were designed which inherit dielectric and magnetic attributes from PANI and MWCNT respectively. The high ...resolution transmission electron microscopy image shows the PANI coating over MWCNT containing entrapped Fe catalyst. These blends show absorption dominated total shielding effectiveness (
SE
T
) of −45.7
dB (>99.99% attenuation) in the 12.4–18.0
GHz range, suggesting their utility for making efficient microwave absorbers. The enhanced
SE
T
was ascribed to optimization of conductivity, skin-depth, complex permittivity and permeability. A good agreement between theoretical and experimental shielding measurements was also observed.
•Epoxy coatings with chitosan-polypyrrole-SiO2 composites are designed.•Composites cause significant improvement in the corrosion resistance of coatings.•The synergy of chitosan-polypyrrole inhibits ...the diffusion of chloride ions.•SiO2 particles as fillers reinforce the corrosion resistance of the composite.
Chitosan-polypyrrole-SiO2 composites were synthesized by chemical oxidative polymerization of pyrrole in chitosan solution using FeCl3 as an oxidant. The synthesized composites were loaded in epoxy resin and subsequently coated on mild steel substrate using powder coating technique. XRD and FTIR analyses show interaction between chitosan and polypyrrole. Microstructural analyses reveal the formation of polymer particles with distinct spherical morphology. SiO2 particles embedded in the polymer matrix are clearly noticed from the FESEM micrographs. TGA thermogram shows good thermal stability of chitosan-polymer composite. DSC curves reveal a high cross linking density for epoxy coatings loaded with chitosan composite. Tafel plots exhibit significantly high corrosion protection efficiency (99.99%) for the epoxy coatings with 2.0wt% loading of chitosan-polymer composite. The weight loss measurements and salt spray test results clearly exhibit superior corrosion resistance offered by coatings with chitosan-polymer composite. The synergistic interaction between the chitosan and the polypyrrole in the composite is expected to improve the corrosion resistance properties of the coatings. The SiO2 particles present in the composite reinforce the integrity of the coating under corrosive conditions.
•In-situ synthesis of NiCoFe2O4 nanoparticles along with reduced graphene oxide.•The synthesis process results in the formation of RGO layers decorated with ferrite nanoparticles.•The composite shows ...shielding effectiveness value of 36.3 dB (~ 99.98% attenuation) dominated by absorption.•Shielding properties depends upon the concentration of RGO and synergy between the RGO and ferrite nanoparticles.
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With the rapid evolution of wireless communication technology, microwave absorbing materials having broad frequency bandwidth has been at center stage. Present article reports the direct facile method for synthesis of Ni0.5Co0.5Fe2O4 nanoparticles decorated reduced graphene oxide (RGO) nanocomposites (NG) by insitu genesis of Ni0.5Co0.5Fe2O4 nanoparticles in graphene oxide heterogeneous mixture, preceded by hydrazine reduction and calcination. Because of magnetic Ni0.5Co0.5Fe2O4 and dielectric reduced graphene oxide, the intercalated microstructure of NG nanocomposites shows increased shielding effectiveness due to absorption with major contribution from strong conduction loss, polarization effects, enhanced attenuation ability, eddy current losses and multiple scattering. Consequently, the shielding effectiveness of 36.3 dB (~99.98% attenuation of the electromagnetic wave) has been attained in 12.4–18 GHz for a corresponding thickness of 2 mm. The results indicates that the interface linkages and synergy among Ni0.5Co0.5Fe2O4 and RGO plays an important role in improvement of microwave absorbing properties and hence in designing of lightweight microwave absorbers.
