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Effect of the carbon nanotube surface characteristics on the conductivity and dielectric constant of carbon nanotube/poly(vinylidene fluoride) composites.

Carabineiro SA, Pereira MF, Pereira JN, Caparros C, Sencadas V, Lanceros-Mendez S - Nanoscale Res Lett (2011)

Bottom Line: Commercial multi-walled carbon nanotubes (CNT) were functionalized by oxidation with HNO3, to introduce oxygen-containing surface groups, and by thermal treatments at different temperatures for their selective removal.CNT/poly(vinylidene fluoride) composites were prepared using the above CNT samples, with different filler fractions up to 1 wt%.It was found that oxidation reduced composite conductivity for a given concentration, shifted the percolation threshold to higher concentrations, and had no significant effect in the dielectric response.

View Article: PubMed Central - HTML - PubMed

Affiliation: Universidade do Porto, Faculdade de Engenharia, Laboratório de Catálise e Materiais (LCM), LSRE/LCM - Laboratório Associado, Rua Dr, Roberto Frias, s/n, 4200-465 Porto, Portugal. sonia.carabineiro@fe.up.pt.

ABSTRACT
Commercial multi-walled carbon nanotubes (CNT) were functionalized by oxidation with HNO3, to introduce oxygen-containing surface groups, and by thermal treatments at different temperatures for their selective removal. The obtained samples were characterized by adsorption of N2 at -196°C, temperature-programmed desorption and determination of pH at the point of zero charge. CNT/poly(vinylidene fluoride) composites were prepared using the above CNT samples, with different filler fractions up to 1 wt%. It was found that oxidation reduced composite conductivity for a given concentration, shifted the percolation threshold to higher concentrations, and had no significant effect in the dielectric response.

No MeSH data available.


TPD spectra of the CNT samples before and after the oxidizing treatments: CO2 (a) and CO (b) evolution.
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Figure 2: TPD spectra of the CNT samples before and after the oxidizing treatments: CO2 (a) and CO (b) evolution.

Mentions: Figure 2 shows the TPD spectra of the CNT before and after the different treatments. It is clear that the treatment with HNO3 produces a large amount of acidic oxygen groups, such as carboxylic acids, anhydrides, and lactones, which decompose to release CO2. Part of these groups (carboxylic acids) is removed by heating at 400°C. A treatment at 900°C removes all the groups, so that the obtained sample is similar to the original. The total amounts of CO and CO2 evolved from the samples, obtained by integration of the TPD spectra, are presented in Table 1.


Effect of the carbon nanotube surface characteristics on the conductivity and dielectric constant of carbon nanotube/poly(vinylidene fluoride) composites.

Carabineiro SA, Pereira MF, Pereira JN, Caparros C, Sencadas V, Lanceros-Mendez S - Nanoscale Res Lett (2011)

TPD spectra of the CNT samples before and after the oxidizing treatments: CO2 (a) and CO (b) evolution.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211369&req=5

Figure 2: TPD spectra of the CNT samples before and after the oxidizing treatments: CO2 (a) and CO (b) evolution.
Mentions: Figure 2 shows the TPD spectra of the CNT before and after the different treatments. It is clear that the treatment with HNO3 produces a large amount of acidic oxygen groups, such as carboxylic acids, anhydrides, and lactones, which decompose to release CO2. Part of these groups (carboxylic acids) is removed by heating at 400°C. A treatment at 900°C removes all the groups, so that the obtained sample is similar to the original. The total amounts of CO and CO2 evolved from the samples, obtained by integration of the TPD spectra, are presented in Table 1.

Bottom Line: Commercial multi-walled carbon nanotubes (CNT) were functionalized by oxidation with HNO3, to introduce oxygen-containing surface groups, and by thermal treatments at different temperatures for their selective removal.CNT/poly(vinylidene fluoride) composites were prepared using the above CNT samples, with different filler fractions up to 1 wt%.It was found that oxidation reduced composite conductivity for a given concentration, shifted the percolation threshold to higher concentrations, and had no significant effect in the dielectric response.

View Article: PubMed Central - HTML - PubMed

Affiliation: Universidade do Porto, Faculdade de Engenharia, Laboratório de Catálise e Materiais (LCM), LSRE/LCM - Laboratório Associado, Rua Dr, Roberto Frias, s/n, 4200-465 Porto, Portugal. sonia.carabineiro@fe.up.pt.

ABSTRACT
Commercial multi-walled carbon nanotubes (CNT) were functionalized by oxidation with HNO3, to introduce oxygen-containing surface groups, and by thermal treatments at different temperatures for their selective removal. The obtained samples were characterized by adsorption of N2 at -196°C, temperature-programmed desorption and determination of pH at the point of zero charge. CNT/poly(vinylidene fluoride) composites were prepared using the above CNT samples, with different filler fractions up to 1 wt%. It was found that oxidation reduced composite conductivity for a given concentration, shifted the percolation threshold to higher concentrations, and had no significant effect in the dielectric response.

No MeSH data available.