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Inorganic nanotubes reinforced polyvinylidene fluoride composites as low-cost electromagnetic interference shielding materials.

Eswaraiah V, Sankaranarayanan V, Ramaprabhu S - Nanoscale Res Lett (2011)

Bottom Line: Homogeneous distribution of f-MWCNTs and MNTs in PVDF matrix were confirmed by field emission scanning electron microscopy.The addition of 2 wt.% of MNTs (2 wt.%, f-MWCNTs) to PVDF matrix results in an increase in the electrical conductivity from 10-16S/m to 4.5 × 10-5S/m (3.2 × 10-1S/m).EMI SE of approximately 20 dB has been obtained with the addition of 5 wt.% MNTs-1 wt.% f-MWCNTs to PVDF in comparison with EMI SE of approximately 18 dB for 7 wt.% of f-MWCNTs indicating the potential use of the present MNT/f-MWCNT/PVDF composite as low-cost EMI shielding materials in X-band region.

View Article: PubMed Central - HTML - PubMed

Affiliation: Alternative Energy and Nanotechnology Laboratory (AENL), Nano Functional Materials, Technology Centre (NFMTC), Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India. ramp@iitm.ac.in.

ABSTRACT
Novel polymer nanocomposites comprising of MnO2 nanotubes (MNTs), functionalized multiwalled carbon nanotubes (f-MWCNTs), and polyvinylidene fluoride (PVDF) were synthesized. Homogeneous distribution of f-MWCNTs and MNTs in PVDF matrix were confirmed by field emission scanning electron microscopy. Electrical conductivity measurements were performed on these polymer composites using four probe technique. The addition of 2 wt.% of MNTs (2 wt.%, f-MWCNTs) to PVDF matrix results in an increase in the electrical conductivity from 10-16S/m to 4.5 × 10-5S/m (3.2 × 10-1S/m). Electromagnetic interference shielding effectiveness (EMI SE) was measured with vector network analyzer using waveguide sample holder in X-band frequency range. EMI SE of approximately 20 dB has been obtained with the addition of 5 wt.% MNTs-1 wt.% f-MWCNTs to PVDF in comparison with EMI SE of approximately 18 dB for 7 wt.% of f-MWCNTs indicating the potential use of the present MNT/f-MWCNT/PVDF composite as low-cost EMI shielding materials in X-band region.

No MeSH data available.


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Experimental setup for EMI shielding characteristic measurements of polymer composites.
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Figure 1: Experimental setup for EMI shielding characteristic measurements of polymer composites.

Mentions: The direct current (DC) volume electrical conductivity of the composites was measured at room temperature using homemade resistivity setup with the help of Keithley 2400 sourcemeter and 2182 nanovoltmeter. The high resistance of the films was measured with a 617 programmable electrometer and a 6517B high-resistance electrometer. The EMI shielding measurement was performed with an Agilent E8362B vector network analyzer using a 201-point averaging in the frequency range of 8 to 12 GHz (X-band). Figure 1 shows the pictorial representation of the experimental setup for measuring the shielding effectiveness of the composite materials. Here, we followed the transmission line technique using an X-band waveguide sample holder for measuring scattering parameters of the composites. Samples of dimensions 22.84 × 10.16 mm2 were prepared and kept inside the waveguide. The EMI shielding effectiveness is defined as the ratio of incoming (Pi) to outgoing power (Po) of radiation. Shielding effectiveness (SE) = 10 log (Pi/Po) and is defined in decibels (dB). The higher the value in decibels, the less energy passes through the material. When electromagnetic radiation falls on the shielding material, reflection, absorption, and transmission are observed. The corresponding reflectivity (R), absorptivity (A), and transmissivity (T) are according to the equation A + R + T = 1. R and T can be calculated from the measured scattering coefficients, from the relations S12 = 10 log T and S11 = 10 log R. The cross-sectional morphology of the composites were observed using field emission scanning electron microscope (FESEM, QUANTA 3 D, FEI) and transmission electron microscope. X-ray elemental mapping was also performed using EDX genesis software. Powder X-ray diffraction (XRD) studies were carried out using X'Pert PRO, PANalytical diffractometer with nickel filter Cu Kα radiation as the X-ray source. The samples were scanned in steps of 0.016° in the 2θ range 10 to 80. For the determination of functional groups, a Fourier transform infrared spectrum was acquired using Perkin Elmer FTIR spectrometer from 400 to 4,000 cm-1. The chemical resistance of the composites in different acids, bases, alkanes and organic solvents was estimated by measuring the weight of the sample before and after treatment with these chemicals using METTLER TOLEDO XS 105 weighing balance.


Inorganic nanotubes reinforced polyvinylidene fluoride composites as low-cost electromagnetic interference shielding materials.

Eswaraiah V, Sankaranarayanan V, Ramaprabhu S - Nanoscale Res Lett (2011)

Experimental setup for EMI shielding characteristic measurements of polymer composites.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211184&req=5

Figure 1: Experimental setup for EMI shielding characteristic measurements of polymer composites.
Mentions: The direct current (DC) volume electrical conductivity of the composites was measured at room temperature using homemade resistivity setup with the help of Keithley 2400 sourcemeter and 2182 nanovoltmeter. The high resistance of the films was measured with a 617 programmable electrometer and a 6517B high-resistance electrometer. The EMI shielding measurement was performed with an Agilent E8362B vector network analyzer using a 201-point averaging in the frequency range of 8 to 12 GHz (X-band). Figure 1 shows the pictorial representation of the experimental setup for measuring the shielding effectiveness of the composite materials. Here, we followed the transmission line technique using an X-band waveguide sample holder for measuring scattering parameters of the composites. Samples of dimensions 22.84 × 10.16 mm2 were prepared and kept inside the waveguide. The EMI shielding effectiveness is defined as the ratio of incoming (Pi) to outgoing power (Po) of radiation. Shielding effectiveness (SE) = 10 log (Pi/Po) and is defined in decibels (dB). The higher the value in decibels, the less energy passes through the material. When electromagnetic radiation falls on the shielding material, reflection, absorption, and transmission are observed. The corresponding reflectivity (R), absorptivity (A), and transmissivity (T) are according to the equation A + R + T = 1. R and T can be calculated from the measured scattering coefficients, from the relations S12 = 10 log T and S11 = 10 log R. The cross-sectional morphology of the composites were observed using field emission scanning electron microscope (FESEM, QUANTA 3 D, FEI) and transmission electron microscope. X-ray elemental mapping was also performed using EDX genesis software. Powder X-ray diffraction (XRD) studies were carried out using X'Pert PRO, PANalytical diffractometer with nickel filter Cu Kα radiation as the X-ray source. The samples were scanned in steps of 0.016° in the 2θ range 10 to 80. For the determination of functional groups, a Fourier transform infrared spectrum was acquired using Perkin Elmer FTIR spectrometer from 400 to 4,000 cm-1. The chemical resistance of the composites in different acids, bases, alkanes and organic solvents was estimated by measuring the weight of the sample before and after treatment with these chemicals using METTLER TOLEDO XS 105 weighing balance.

Bottom Line: Homogeneous distribution of f-MWCNTs and MNTs in PVDF matrix were confirmed by field emission scanning electron microscopy.The addition of 2 wt.% of MNTs (2 wt.%, f-MWCNTs) to PVDF matrix results in an increase in the electrical conductivity from 10-16S/m to 4.5 × 10-5S/m (3.2 × 10-1S/m).EMI SE of approximately 20 dB has been obtained with the addition of 5 wt.% MNTs-1 wt.% f-MWCNTs to PVDF in comparison with EMI SE of approximately 18 dB for 7 wt.% of f-MWCNTs indicating the potential use of the present MNT/f-MWCNT/PVDF composite as low-cost EMI shielding materials in X-band region.

View Article: PubMed Central - HTML - PubMed

Affiliation: Alternative Energy and Nanotechnology Laboratory (AENL), Nano Functional Materials, Technology Centre (NFMTC), Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India. ramp@iitm.ac.in.

ABSTRACT
Novel polymer nanocomposites comprising of MnO2 nanotubes (MNTs), functionalized multiwalled carbon nanotubes (f-MWCNTs), and polyvinylidene fluoride (PVDF) were synthesized. Homogeneous distribution of f-MWCNTs and MNTs in PVDF matrix were confirmed by field emission scanning electron microscopy. Electrical conductivity measurements were performed on these polymer composites using four probe technique. The addition of 2 wt.% of MNTs (2 wt.%, f-MWCNTs) to PVDF matrix results in an increase in the electrical conductivity from 10-16S/m to 4.5 × 10-5S/m (3.2 × 10-1S/m). Electromagnetic interference shielding effectiveness (EMI SE) was measured with vector network analyzer using waveguide sample holder in X-band frequency range. EMI SE of approximately 20 dB has been obtained with the addition of 5 wt.% MNTs-1 wt.% f-MWCNTs to PVDF in comparison with EMI SE of approximately 18 dB for 7 wt.% of f-MWCNTs indicating the potential use of the present MNT/f-MWCNT/PVDF composite as low-cost EMI shielding materials in X-band region.

No MeSH data available.


Related in: MedlinePlus