Mild hydrothermal treatment to prepare highly dispersed multi-walled carbon nanotubes

Zhang, Li; Hashimoto, Yuichi; Taishi, Toshinori; Ni, Qing‐Qing

doi:10.1016/j.apsusc.2010.08.106

Cited by 40 publications

(19 citation statements)

References 31 publications

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“…Two types of mild hydrothermal treatment were conducted, as reported by our research group in Ref. [20], with some modifications. Pure water, potassium hydroxide (KOH), and potassium persulfate (KPS) were used in the treatment, and they were also obtained from Wako Pure Chemical Industries Ltd., Japan.…”

Section: Modification Of Cntsmentioning

confidence: 99%

“…To improve the dispersion of CNTs, they conducted strong acid treatment. In contrast, a mild hydrothermal treatment that is environment friendly, fast, and allows for easy modification has been performed [20]. No harsh organic or aqueous solvents were used in this process, and it is thus a less destructive modification route.…”

Section: Introductionmentioning

confidence: 95%

“…However, CNTs disperse poorly in organic and aqueous solvents because of a strong intrinsic van der Waals attraction [18][19][20]. Sahoo et al [21] investigated the influence of CNTs in a PU nanocomposites actuator.…”

Section: Introductionmentioning

confidence: 98%

“…PU are insulators, and they are generally light, soft, flexible and easy to fabricate, and have been reported to generate deformation and large strain under electric field stimulation [3,7,10,14]. Conversely, carbon nanotubes (CNTs) are also light, possess a high aspect ratio, and have outstanding mechanical, chemical, and electric properties [3,6,8,[16][17][18][19][20]. CNTs can improve the mechanical and electrical properties of polymer-based composites and are thus a good candidate for use as a filler in actuators.…”

Section: Introductionmentioning

confidence: 98%

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Behavior of polymer-based electroactive actuator incorporated with mild hydrothermally treated CNTs

Melvin

Natsuki

2014

Appl. Phys. A

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We fabricated an actuator that was made from polyurethane (PU) with carbon nanotubes (CNTs) as the filler. To improve the dispersion of the CNTs, a mild hydrothermal treatment was carried out. Carboxyl and hydroxyl groups were introduced to the surface of the CNTs, and they were found to be highly dispersed in polar solvents such as dimethylformamide. To evaluate these films, we mainly focused on electrical properties, such as dielectric spectroscopy, space charge measurements, and actuator behavior. We found that the PU/CNTs film bents toward the cathode when an electric field was applied, and it reverted to its original position when the electric field was removed. Upon the inclusion of the CNTs as the filler for the polymer, the electrical properties of the films improved significantly. The highly polarized films had a high relative permittivity, and this produced a higher Maxwell pressure, which assisted the actuation. A high accumulated charge density was observed from space charge measurements in some of the films, and this explains the bending direction and the actuation mechanism.

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Section: Modification Of Cntsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

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Behavior of polymer-based electroactive actuator incorporated with mild hydrothermally treated CNTs

Melvin

Natsuki

2014

Appl. Phys. A

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“…Oxidative functionalization of MWCNTs was performed by autoclavation in alkaline aqueous solution of potassium peroxydisulfate according to the procedure reported in literature [11].…”

Section: Functionalization Of Cntsmentioning

confidence: 99%

High-temperature resistivity of aluminum–carbon nanotube composites

2015

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The resistivity and thermal coefficient of\ud resistivity (TCR), of metallic matrix composites, MMCs,\ud aluminum–carbon nanotube, Al-CNT, were studied under\ud high vacuum in the temperature interval from RT to 800 K.\ud The samples shaped as small cylinders and containing\ud single-walled CNTs or multi-walled CNTs were sintered at\ud 625 C. The resistivity of sintered samples of pure Al was\ud found three orders of magnitude higher with respect to\ud bulk, having the former a density value equal to 98.8 % of\ud bulk Al. The explored range of the CNT concentration was\ud within 5 wt%. At the highest CNT concentrations, the\ud trend of resistivity against temperature was found negative\ud being more pronounced for composites with MWCNTs.\ud For Al-SWCNT composites, at around 3.3 wt%\ud (4.2 vol%), TCR is practically independent from temperature;\ud for Al-MWCNT, the TCR zero-crossing occurs at\ud different compositions depending on temperature. Higher\ud is the temperature, lower is the TCR zero-crossing composition.\ud Resistivity data were discussed in the framework\ud of the Matthiessen’s rule and sound evidences were shown\ud that no Al4C3 formation was detected at working\ud temperatures

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