Growth of Carbon Nanotubes and Carbon Nanofibers in Opposed Flow Oxy-Flame of Methane

2003 ◽  
Author(s):  
W. Merchan-Merchan ◽  
A. V. Saveliev ◽  
L. A. Kennedy
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanofibers ◽  
Carbon Nanomaterials ◽  
Rectangular Cross Section ◽  
Formation Rate ◽  
Field Method ◽  
Great Promise ◽  
Multiwalled Carbon ◽  
Catalytic Support ◽  
Opposed Flow

Carbon nanotubes and carbon nanofibers formed on a Ni-based catalytic support positioned at the fuel side of opposed flow oxy-flame are characterized by electron microscopy. Observed nanoforms include multiwalled carbon nanotubes (MWNTs), MWNT bundles, helically coiled tubular nanofibers, and ribbon-like coiled nanofibers with rectangular cross-section. The electric field method is applied to control structure and purity of formed carbon nanomaterial. A coating layer of nanotubes possessing a thickness of 35 to 40 microns and a high degree of alignment was formed along the surface of the catalytic probe with variation of probe potential. The method shows a great promise in controlling the structure and formation rate of flame generated carbon nanomaterials.

scholarly journals Biotransformation of Pristine and Oxidized Carbon Nanotubes by the White Rot Fungus Phanerochaete chrysosporium

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1340 ◽  
Author(s):  
Qiang Ma ◽  
Ailimire Yilihamu ◽  
Zhu Ming ◽  
Shengnan Yang ◽  
Mengyao Shi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Phanerochaete Chrysosporium ◽  
Environmental Remediation ◽  
Carbon Nanomaterials ◽  
Carbon Skeleton ◽  
White Rot ◽  
White Rot Fungus ◽  
Multiwalled Carbon ◽  
Complete Degradation

Carbon nanomaterials are widely studied and applied nowadays, with annual production increasing. After entering the environment, the complete degradation of these carbon nanomaterials by microorganisms is proposed as an effective approach for detoxification and remediation. In this study, we evaluated the degradation of pristine multiwalled carbon nanotubes (p-MWCNTs) and oxidized multiwalled carbon nanotubes (o-MWCNTs) by the white rot fungus Phanerochaete chrysosporium, which is a powerful decomposer in the carbon cycle and environmental remediation. Both p-MWCNTs and o-MWCNTs were partially oxidized by P. chrysosporium as indicated by the addition of oxygen atoms to the carbon skeleton in the forms of C=O and O–H bonds. The fungal oxidation led to the shortening of MWCNTs, where precipitated o-MWCNTs showed more short tubes. During the transformation, the defects on the tubes became detached from the carbon skeleton, resulting in decreases of the ID/IG (intensity of D-band/ intensity of G-band) values in Raman spectra. The transformation mechanism was attributed to the enzymatic degradation by laccase and manganese peroxidase excreted by P. chrysosporium. The results collectively indicated that MWCNTs could be transformed by P. chrysosporium, but complete degradation could not be achieved in a short time period. The implications on the environmental risks of carbon nanomaterials are discussed.

The Effect of Nanotube Waviness and Agglomeration on the Elastic Property of Carbon Nanotube-Reinforced Composites

2004 ◽  
Vol 126 (3) ◽  
pp. 250-257 ◽  
Author(s):  
Dong-Li Shi ◽  
Xi-Qiao Feng ◽  
Yonggang Y. Huang ◽  
Keh-Chih Hwang ◽  
Huajian Gao
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Effective Properties ◽  
High Strength ◽  
Elastic Stiffness ◽  
Field Method ◽  
Effective Field ◽  
Great Promise ◽  
Reinforced Composites ◽  
Stiffening Effect

Owing to their superior mechanical and physical properties, carbon nanotubes seem to hold a great promise as an ideal reinforcing material for composites of high-strength and low-density. In most of the experimental results up to date, however, only modest improvements in the strength and stiffness have been achieved by incorporating carbon nanotubes in polymers. In the present paper, the stiffening effect of carbon nanotubes is quantitatively investigated by micromechanics methods. Especially, the effects of the extensively observed waviness and agglomeration of carbon nanotubes are examined theoretically. The Mori-Tanaka effective-field method is first employed to calculate the effective elastic moduli of composites with aligned or randomly oriented straight nanotubes. Then, a novel micromechanics model is developed to consider the waviness or curviness effect of nanotubes, which are assumed to have a helical shape. Finally, the influence of nanotube agglomeration on the effective stiffness is analyzed. Analytical expressions are derived for the effective elastic stiffness of carbon nanotube-reinforced composites with the effects of waviness and agglomeration. It is found that these two mechanisms may reduce the stiffening effect of nanotubes significantly. The present study not only provides the relationship between the effective properties and the morphology of carbon nanotube-reinforced composites, but also may be useful for improving and tailoring the mechanical properties of nanotube composites.

Field electron emission of multiwalled carbon nanotubes and carbon nanofibers grown from Camphor

2008 ◽  
Vol 52 (6) ◽  
pp. 941-945 ◽  
Author(s):  
Savita P. Somani ◽  
Prakash R. Somani ◽  
A. Yoshida ◽  
M. Tanemura ◽  
S.P. Lau ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Carbon Nanofibers ◽  
Electron Emission ◽  
Field Electron Emission ◽  
Multiwalled Carbon ◽  
Field Electron

Properties of epoxy nanocomposites filled with carbon nanomaterials

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Young Seok Song ◽  
Jae Ryoun Youn
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Thermal Properties ◽  
Carbon Nanomaterials ◽  
Rheological Behaviour ◽  
Epoxy Composites ◽  
Mechanical And Thermal Properties ◽  
Epoxy Nanocomposites ◽  
Multiwalled Carbon ◽  
Weight Content

Abstract Rheological, mechanical, electrical, and thermal properties of epoxy nanocomposites containing carbon nanomaterials (CNMs) were investigated with different loading. Two kinds of CNMs - multiwalled carbon nanotubes (MWNTs) and carbon blacks (CBs) - were selected to examine the effect of their geometrical structure on various properties. Under sonication, MWNTs and CBs (0.5, 1.0, and 1.5 wt.-%) were mixed with the epoxy resin by using a solvent. Dispersion of the CNMs in the epoxy nanocomposites was characterized by means of transmission electron microscopy and field emission scanning electron microscopy. Carbon nanotubes (CNTs)/epoxy composites show significant differences from the CBs/ epoxy composites due to their high aspect ratio. It was found that the CNTs/epoxy composites exhibit non-Newtonian rheological behaviour, while the CBs/epoxy composites with the same weight content show Newtonian behaviour. The CNTs/ epoxy composites have better mechanical and thermal properties than the CBs/ epoxy composites. In the CNTs nanocomposites, the percolation threshold of electrical conductivity is found to be less than 0.5 wt.-%, which is too low to be obtained by using other carbon materials such as carbon fibre in polymer composites. Effects of CNM content on the various properties were also examined. As loading of the CNMs increased, improved results were obtained.

Shape-Memory Nanocomposite Elastomers Filled with Carbon Nanomaterials

2016 ◽  
Vol 100 ◽  
pp. 5-10
Author(s):  
Giuseppe Cesare Lama ◽  
Gennaro Gentile ◽  
Pierfrancesco Cerruti ◽  
Marino Lavorgna ◽  
Veronica Ambrogi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Shape Memory ◽  
Carbon Nanomaterials ◽  
Thermomechanical Analysis ◽  
Scanning Calorimetry ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
Dispersion Test ◽  
Surface Modified ◽  
Modified Carbon Nanotubes

In this contribution, the preparation and characterization of new shape-memory epoxy based nanocomposites filled with modified multiwalled carbon nanotubes are reported. The study has been focused on the optimization of the preparation methodology and on the evaluation of the effect of different contents of surface modified carbon nanotubes on the properties and the microstructure of the obtained materials. In particular, dispersion test, infrared spectroscopy, thermogravimetric analysis and bright field transmission electron microscopy have been carried out to analyze the modified filler. Moreover, the obtained nanocomposites have been characterized by morphological analysis, differential scanning calorimetry, thermomechanical analysis and X-ray analysis in order to clarify the effect of the nanofiller on the structure and shape memory properties of the materials.

scholarly journals Spongy Structures Coated with Carbon Nanomaterials for Efficient Oil/Water Separation

2017 ◽  
Vol 19 (2) ◽  
pp. 127 ◽  
Author(s):  
Fail Sultanov ◽  
B. Bakbolat ◽  
Zulkhair Mansurov ◽  
Shin-Shem Pei ◽  
Rabi Ebrahim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Oil Spill ◽  
Carbon Nanomaterials ◽  
Petroleum Products ◽  
Dip Coating ◽  
Organic Liquids ◽  
Multiwalled Carbon ◽  
Water Separation ◽  
Coating Method

Rapid progress of processing and transportation of oil and petroleum products may cause disaster for environment like oil spill. Oil booms, combustion, and oil skimmer vessels are usually used to clean up the oil spill, but often with poor efficiency and even with undesirable environmental side effects. With obtaining of carbon nanomaterials (CNMs) (graphene, carbon nanotubes) and developing inexpensive technologies for their synthesis it has become perspective to use them for creation of 3D structures which may serve as a hydrophobic sorbents for oil and petroleum products. In this study, sponges coated with carbon nanomaterials were obtained using “dip-coating” method. Walls of commercially available polyurethane (PU) and melamine sponges were coated with reduced graphene oxide (rGO) and multiwalled carbon nanotubes (MWCNTs). The resulting sponges are characterized by excellent mechanical properties, they are superhydprophobic, and they fully repel water and at the same time selectively absorb oil and organic liquids of different densities. We believe that superhydrophobic and superoleophilic sponges, the walls of which are coated with CNMs, are perspective candidates for reusable sorbents for collection of oil and petroleum products from the surface of water and moreover due to its excellent mechanical properties they can serve as a hydrophobic filtering materials for separation of oil from the surface of water.

scholarly journals Electrical properties of compacted carbon nanomaterials

2021 ◽  
Vol 340 ◽  
pp. 01047
Author(s):  
Nikita I. Lapekin ◽  
Artem A. Shestakov ◽  
Andrey E. Brester ◽  
Arina V. Ukhina ◽  
Alexander G. Bannov
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Properties ◽  
Carbon Nanofibers ◽  
Carbon Nanomaterials ◽  
Frequency Range ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Cylindrical Samples

In this paper, the electrical properties of various compacted carbon nanomaterials were investigated. Compacted carbon nanomaterials (carbon nanofibers, multi-walled carbon nanotubes) were compacted into cylindrical samples and the electrical properties were measured in a frequency range from 50 Hz to 1MHz.

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