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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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EMI shielding effectiveness of MNTs/PVDF, MNTs/f-MWCNTs/PVDF and f-MWCNTs/PVDF composites.
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Figure 10: EMI shielding effectiveness of MNTs/PVDF, MNTs/f-MWCNTs/PVDF and f-MWCNTs/PVDF composites.

Mentions: The EMI SE of MNTs/PVDF composites with various mass fractions of MNTs as a function of frequency are presented in Figure 10a. The results show that EMI shielding effectiveness of pure PVDF is almost 0.3 dB indicating that it is transparent to the electromagnetic radiation throughout the measured frequency. This is probably due to its electrically insulating nature. It is observed that EMI SE starts increasing with the addition of MNTs to the insulating PVDF matrix. The EMI SE for 1 wt.% MNTs filled PVDF composite is found to be 2.27 dB and it increases further to 5.14 and 11 dB at higher loading of MNTs of 3 and 5 wt.%, respectively. Hence, it is clear that the major contribution to the EMI shielding comes from the addition of semiconducting MNTs to the PVDF matrix. This increment in EMI SE can be attributed to the formation of conductive and connective network in the PVDF matrix, which is in accordance with the high-resolution FESEM image of MNTs filled PVDF composite (Figure 5f). Since electrical conductivity of the MNTs is two orders less compared to that of carbon nanotubes, there is a limit over the highest obtainable conductivity of the total composite. This limits the EMI SE to approximately 12 dB for 5 wt.% MNTs/PVDF composite. These results suggest that the MNTs/PVDF composites can be used for electrostatic discharge applications. In order to make it suitable for EMI shielding applications, a small amount of (1 wt.%) f-MWCNTs have been incorporated in MNT/PVDF matrix. With this, 1 wt.% f-MWCNTs in 5 wt.% MNTs/PVDF composite, we could achieve an EMI SE of 18 to 22 dB. For comparison, the EMI SE of 7 wt.% f-MWCNTs/PVDF composites alone in the same frequency region has been measured, and in this case, an EMI SE of 18 dB has been obtained as shown in Figure 10c. Table 2 shows the overall EMI SE of different composites and their electrical conductivities. It is clear that 5 wt.% MNTs-1 wt.% f-MWCNTs-PVDF composite can be a better and low-cost EMI shielding material.


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

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

EMI shielding effectiveness of MNTs/PVDF, MNTs/f-MWCNTs/PVDF and f-MWCNTs/PVDF composites.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 10: EMI shielding effectiveness of MNTs/PVDF, MNTs/f-MWCNTs/PVDF and f-MWCNTs/PVDF composites.
Mentions: The EMI SE of MNTs/PVDF composites with various mass fractions of MNTs as a function of frequency are presented in Figure 10a. The results show that EMI shielding effectiveness of pure PVDF is almost 0.3 dB indicating that it is transparent to the electromagnetic radiation throughout the measured frequency. This is probably due to its electrically insulating nature. It is observed that EMI SE starts increasing with the addition of MNTs to the insulating PVDF matrix. The EMI SE for 1 wt.% MNTs filled PVDF composite is found to be 2.27 dB and it increases further to 5.14 and 11 dB at higher loading of MNTs of 3 and 5 wt.%, respectively. Hence, it is clear that the major contribution to the EMI shielding comes from the addition of semiconducting MNTs to the PVDF matrix. This increment in EMI SE can be attributed to the formation of conductive and connective network in the PVDF matrix, which is in accordance with the high-resolution FESEM image of MNTs filled PVDF composite (Figure 5f). Since electrical conductivity of the MNTs is two orders less compared to that of carbon nanotubes, there is a limit over the highest obtainable conductivity of the total composite. This limits the EMI SE to approximately 12 dB for 5 wt.% MNTs/PVDF composite. These results suggest that the MNTs/PVDF composites can be used for electrostatic discharge applications. In order to make it suitable for EMI shielding applications, a small amount of (1 wt.%) f-MWCNTs have been incorporated in MNT/PVDF matrix. With this, 1 wt.% f-MWCNTs in 5 wt.% MNTs/PVDF composite, we could achieve an EMI SE of 18 to 22 dB. For comparison, the EMI SE of 7 wt.% f-MWCNTs/PVDF composites alone in the same frequency region has been measured, and in this case, an EMI SE of 18 dB has been obtained as shown in Figure 10c. Table 2 shows the overall EMI SE of different composites and their electrical conductivities. It is clear that 5 wt.% MNTs-1 wt.% f-MWCNTs-PVDF composite can be a better and low-cost EMI shielding material.

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