scholarly journals Measurement of Flexural Rigidity of Multi-Walled Carbon Nanotubes by Dynamic Scanning Electron Microscopy

Fibers ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 31 ◽  
Author(s):  
Renata Fortini ◽  
Asmus Meyer-Plath ◽  
Dominic Kehren ◽  
Ulrich Gernert ◽  
Leonardo Agudo Jácome ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Flexural Rigidity ◽  
Toxicological Studies ◽  
Resonance Frequencies ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Dynamic Scanning ◽  
Scanning Electron

In this work the flexural rigidity of individual large diameter multi-walled carbon nanotubes (MWCNTs) was investigated. The bending modulus were obtained by detecting the resonance frequencies of mechanically excited cantilevered carbon nanotubes using the so-called dynamic scanning electron microscopy technique, and applying the Euler–Bernoulli beam theory. For the nanotubes studied, we determined a modulus of up to 160 GPa. This agrees with values reported by other authors for MWCNTs produced by catalytic chemical vapor deposition, however, it is 6-8 times smaller than values reported for single and multi-walled carbon nanotubes produced by arc-discharge synthesis. Toxicological studies with carbon nanotubes have been showing that inhaled airborne nanofibers that reach the deep airways of the respiratory system may lead to serious, asbestos-like lung diseases. These studies suggested that their toxicity critically depends on the fiber flexural rigidity, with high rigidity causing cell lesions. To complement the correlation between observed toxicological effects and fiber rigidities, reliable and routinely applicable measurement techniques for the flexural rigidity of nanofibers are required.

scholarly journals Polymeric Composites Based on Polyurea Matrix Reinforced with Carbon Nanotubes

2017 ◽  
Vol 54 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Maria Adina Vulcan ◽  
Celina Damian ◽  
Paul Octavian Stanescu ◽  
Eugeniu Vasile ◽  
Razvan Petre ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

This paper deals with the synthesis of polyurea and its use as polymer matrix for nanocomposites reinforced with multi-walled carbon nanotubes (MWCNT). Two types of materials were obtained during this research, the first cathegory uses the polyurea as matrix and the second one uses a mixture between epoxy resin and polyurea. The nanocomposites were characterized by Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM) and Tensile Tests .The elastomeric features of nanocomposites were highlighted by the results which showed low value of Tg. Also higher thermal stability with ~40oC compared with commercial products (M20) were observed, but lower mechanical properties compared to neat polyurea.

scholarly journals Microstructure and microwave absorbing properties of reduced graphene oxide/Ni/multi-walled carbon nanotubes/Fe3O4 filled monolayer cement–based absorber

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882288 ◽  
Author(s):  
Yafei Sun ◽  
Min Chen ◽  
Peiwei Gao ◽  
Tianshu Zhou ◽  
Hongwei Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Pore Structure ◽  
Reduced Graphene Oxide ◽  
Reduced Graphene ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

In this article, reduced graphene oxide/Ni/multi-walled carbon nanotubes/Fe3O4 filled paste is synthesized with the aim of developing a novel shielding material. To do so, nano-dispersion presenting homogeneous distribution is made by ultrasonic dispersing technology. Next, the effects of nano-absorbent content on the fluidity, mechanical strength, pore structure, resistivity, and absorbing reflectivity of paste are studied. At the end, the microstructure of composite is uncovered by scanning electron microscopy, Fourier transformer infrared, X-ray diffraction images as well as the pore size distribution and absorbing reflectivity are revealed. The results indicate that a small load of reduced graphene oxide and other nano-absorbents can significantly reduce the fluidity and resistivity of paste, but its pore structure is improved so that its mechanical properties are increased. Scanning electron microscopy images indicate that reduced graphene oxide promotes the increasing and thickening of the cement hydration products as well as the growth of a large number of flower-like and compact bulk crystals. Furthermore, the minimum reflectivity of −10.6 dB is obtained in the range of 2–18 GHz while the effective bandwidth of 16 GHz is obtained when reflectivity is less than −5 dB. This research provides a new pathway for the preparation of monolayer cement–based absorber.

Bulk synthesis of multi-walled carbon nanotubes by AC arc discharge method

2017 ◽  
Vol 231 (3) ◽  
pp. 141-151 ◽  
Author(s):  
KK Singh ◽  
SK Chaudhary ◽  
R Venugopal ◽  
A Gaurav
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Arc Discharge ◽  
Pure Graphite ◽  
Multi Walled Carbon Nanotubes ◽  
Different Shapes ◽  
Ac Arc ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

This work proposes the production of multi-walled carbon nanotubes by AC arc discharging of spectroscopically pure graphite electrodes of different shapes, that is, movable cylindrical and stationary rectangular electrode by manual metal arc welding setup. Continuous arc was generated by maintaining the gap of about 3 mm between the electrodes which in turn formed the plasma zone. Vaporization of carbon cations followed by sudden quenching paved the way for formation of carbon nantotubes. Nanotubes produced were deposited on the stationary graphite electrode in the form of soot. Further extraction of the nanoparticles from the soot was performed by conducting series of purification processes which will be discussed in upcoming chapters. Morphology and purity of the extracted nanotubes were investigated by X-ray diffraction, scanning electron microscopy, field-emission scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. Following the characterization process, it was observed that the so-produced nanotubes were of different shapes, that is, carbon cone nanotubes, nanocapsules, nanoparticles and branching type and randomly oriented. The length of the nanotubes varied from 231 to 561 nm, whereas diameter was found to be in the range of 14–55 nm.

Fabrication of a vertically aligned carbon nanotube electrode and its modification by nanostructured MnO2 for supercapacitors

2009 ◽  
Vol 81 (12) ◽  
pp. 2317-2325 ◽  
Author(s):  
Wei-De Zhang ◽  
Jin Chen
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Vertically Aligned ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

Strongly bonded arrays of vertically aligned, multi-walled carbon nanotubes (MWNTs) have been successfully grown on Ta foils, and provide a convenient basis for fabricating electrodes with high conductivity and stability. The MWNT arrays were further coated by nanostructured MnO2 through reacting with KMnO4 solution at room temperature. The morphology of the MnO2/MWNT nanocomposite was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the MnO2 is a beehive-like nanostructure that is homogeneously and densely coated on the surface of the MWNTs. The capacitance of the MWNT electrode was significantly increased from 0.14 to 6.81 mF cm–2 after being modified with nanostructured MnO2, that is, the mass-specific capacitance of the bare and MnO2-modified MWNTs was about 33 and 446 F g–1, respectively. The MnO2/MWNT nanocomposite on Ta foils could be potential for developing a supercapacitor.

Self-Assembly of Aligned Multi-Walled Carbon Nanotubes in Polypropylene-Coated Multi-Walled Carbon Nanotubes Composites

2013 ◽  
Vol 669 ◽  
pp. 55-62 ◽  
Author(s):  
Yi Na Xiong ◽  
Xiao Hua Chen ◽  
Qun Huang ◽  
Long Shan Xu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Self Assembly ◽  
Butyl Methacrylate ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

Polypropylene (PP)-coated multi-walled carbon nanotubes (MWNTs) composite with MWNTs exceptional alignment dispersed and improved mechanical properties was prepared with maleic anhydride (MAH) as a compatibilizer and poly (butyl methacrylate) (PBMA) as a binding. Scanning electron microscopy (SEM) results showed that MWNTs within composite were aligned without aggregation and the oriented MWNTs were connected by matrix. High-resolution transmission electron microscopy (HRTEM) results demonstrated that the nanotubes were densely coated with a PP layer. Infrared spectroscopy (IR) results revealed that there was covalently linkage of MWNTs with PP via MAH. The interactions between MWNTs-PP and MWNTs-PBMA induced orientation of MWNTs. The improved mechanical properties of PP - coated MWNTs composite was also shown.

Scanning electron microscopy of field-emitting individual single-walled carbon nanotubes

2004 ◽  
Vol 85 (1) ◽  
pp. 112-114 ◽  
Author(s):  
Alireza Nojeh ◽  
Wai-Kin Wong ◽  
Aaron W. Baum ◽  
R. Fabian Pease ◽  
Hongjie Dai
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Single Walled Carbon Nanotubes ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

Deposition of Various Metals on Vertically-Aligned Single-Walled Carbon Nanotubes

2007 ◽  
Author(s):  
Kei Ishikawa ◽  
Hai Duong ◽  
Junichiro Shiomi ◽  
Shigeo Maruyama
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Cohesive Energy ◽  
Layer Structure ◽  
Single Walled Carbon Nanotubes ◽  
Single Walled Carbon ◽  
Vertically Aligned ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

Evaporation of different metals (Au, Ti, Al and Pd) onto Vertically-Aligned Single-Walled Carbon Nanotubes (VASWNT) has been studied. Observations through Scanning Electron Microscopy (SEM) showed a clear metal-dependence of the deposition layer structure on top of the VASWNT, reflecting the variation of wettability and cohesive energy of each metal. These characteristics also influence the structures of the metal penetrated through the top surface into VASWNT film, where metal forms particles inside VASWNT film except for Ti. A simple annealing technique to remove metals penetrated in the SWNT films is demonstrated. Some peculiar morphologies found during the processes are also presented.

Preparation of Single-Walled Carbon Nanotubes from Starch by Arc Discharge

2012 ◽  
Vol 454 ◽  
pp. 63-66
Author(s):  
Xia Yuan ◽  
Yu Liang An ◽  
Chen Zhang ◽  
Hong Chao Sui
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Arc Discharge ◽  
Single Walled Carbon Nanotubes ◽  
Single Walled Carbon ◽  
Transmission Electron ◽  
Walled Carbon Nanotubes ◽  
Discharge Method ◽  
Scanning Electron

Single-walled carbon nanotubes (SWNTs) have been successfully prepared from starch by arc discharge technique. The SWNTs products were characterized by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The growth mechanism of the SWNTs was discussed in terms of the starch. The results demonstrate that starch is one of the suitable precursor for making SWNTs by arc discharge method.

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