scholarly journals Effect of Size of Multiwalled Carbon Nanotubes Dispersed in Gear Oils for Improvement of Tribological Properties

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Kodanda Rama Rao Chebattina ◽  
V. Srinivas ◽  
N. Mohan Rao
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Ball Milling ◽  
Multiwalled Carbon Nanotubes ◽  
Tribological Properties ◽  
Extreme Pressure ◽  
Multiwalled Carbon ◽  
Pristine Mwcnts ◽  
Gear Oil ◽  
The Stability

The aim of the paper is to investigate the effect of size of multiwalled carbon nanotubes (MWCNTs) as additives for dispersion in gear oil to improve the tribological properties. Since long pristine MWCNTs tend to form clusters compromising dispersion stability, they are mildly processed in a ball mill to shorten the length and stabilized with a surfactant before dispersing in lubricant. Investigations are made to assess the effect of ball milling on the size and structure of MWCNTs using electron microscopy and Raman spectroscopy. The long and shortened MWCNTs are dispersed in EP 140 gear oil in 0.5% weight. The stability of the dispersed multiwalled carbon nanotubes is evaluated using light scattering techniques. The antiwear, antifriction, and extreme pressure properties of test oils are evaluated on a four-ball wear tester. It is found that ball milling of MWCNTs has a strong effect on the stability and tribological properties of the lubricant. From Raman spectroscopy, it is found that ball milling time of up to 10 hours did not produce any defects on the surface of MWCNTs. The stability of the lubricant and the antiwear, antifriction, and extreme pressure properties have improved significantly with dispersion shortened MWCNTs. Ball milling for longer periods produces defects on the surface of MWCNTs reducing their advantage as oil additives.

Hemostatic Effect of Aminated Multiwalled Carbon Nanotubes/Oxidized Regenerated Cellulose Nanocomposites

2019 ◽  
Vol 19 (11) ◽  
pp. 7410-7415 ◽  
Author(s):  
Baode Zhang ◽  
Ali Nabipour Chakoli ◽  
Jin Mei He ◽  
Yu Dong Huang ◽  
Andrey N. Aleshin
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Regenerated Cellulose ◽  
Oxidized Regenerated Cellulose ◽  
Multiwalled Carbon ◽  
Hemostatic Effect ◽  
Pristine Mwcnts ◽  
Ft Ir ◽  
Cellulose Nanocomposites

We have investigated the covalent conjugation of aminated multiwalled carbon nanotubes (MWCNTNH2)s with Oxidized Regenerated Cellulose (ORC) in order to enhance the hemostatic effect. The MWCNT-NH2s were prepared by functionalization of pristine MWCNTs (pMWCNTs) using amine groups. Neat ORC gauze and MWCNT-NH2s were reacted using glutamic acid as cross linking bridge. We investigated an amination of pMWCNTs as well as the dispersion of MWCNT-NH2s in the ORC gauze as matrix and their interfacial interactions by SEM and FT-IR. The results revealed that relatively strong interaction exists between aminated MWCNTs and the ORC macromolecules. The hydrophilicity test results in the significant increment of water uptake of MWCNT-NH2s/ORC composites with increasing the concentration of MWCNT-NH2s in composite. The in-vitro procoagulation test shows that the MWCNT-NH2s/ORC gauzes have significant procoagulant activity. The hemostatic evaluation of MWCNT-NH2s/ORC composites on rabbits shows that the aminated MWCNTs increase the rate of blood stopping and hence they decrease the blood loosing from injured sites. Hemostatic evaluation indicates that the MWCNT-NH2s/ORC gauze has a valuable hemostatic performance. The products of platelets release reaction, activated platelets glycoprotein and activated clotting enzymes were increased simultaneously. The mechanism of the hemostasis for MWCNT-NH2s/ORC gauze is discussed.

Experimental and theoretical studies on the mechanism for chemical oxidation of multiwalled carbon nanotubes

RSC Advances ◽  
2014 ◽  
Vol 4 (55) ◽  
pp. 28826-28831 ◽  
Author(s):  
B. M. Maciejewska ◽  
M. Jasiurkowska-Delaporte ◽  
A. I. Vasylenko ◽  
K. K. Kozioł ◽  
S. Jurga
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Multiwalled Carbon Nanotubes ◽  
Chemical Oxidation ◽  
Theoretical Studies ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
Experimental And Theoretical Studies

In this study, the oxidation of multiwalled carbon nanotubes (MWCNTs) sonicated and/or refluxed in acids (H2SO4/HNO3) was investigated using a combination of high-resolution transmission electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and ab initio computational methods.

scholarly journals Common Wet Chemical Agents for Purifying Multiwalled Carbon Nanotubes

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Rasel Das ◽  
Md. Eaqub Ali ◽  
Sharifah Bee Abd Hamid ◽  
M. S. M. Annuar ◽  
Seeram Ramakrishna
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Low Cost ◽  
Gravimetric Analysis ◽  
Electrode Arrays ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Pristine Mwcnts ◽  
Transmission Electron ◽  
Wet Chemical

Purification and functionalization of multiwalled carbon nanotubes (MWCNTs) are challenging but vital for their effective applications in various fields including water purification technologies, optoelectronics, biosensors, fuel cells, and electrode arrays. The currently available purification techniques, often complicated and time consuming, yielded shortened and curled MWCNTs that are not suitable for applications in certain fields such as membrane technologies, hybrid catalysis, optoelectronics, and sensor developments. Here we described the H2O2synergy on the actions of HCl and KOH in purifying and functionalizing pristine MWCNTs. The method (HCl/H2O2) showed 100% purification yield as compared to HCl and KOH/H2O2with purification yields 93.46 and 3.92%, respectively. We probed the findings using transmission electron microscope, energy dispersive X-ray spectroscope, attenuated total reflectance infrared spectroscope, Raman spectroscope, thermal gravimetric analysis, and X-ray powder diffraction. The study is a new avenue for simple, rapid, low cost, and scalable purification of pristine MWCNTs for application in versatile fields.

Defect structure of multiwalled carbon nanotubes studied by Raman spectroscopy

2011 ◽  
Vol 47 (5) ◽  
pp. 471-474 ◽  
Author(s):  
E. M. Baitinger ◽  
N. A. Vekesser ◽  
I. N. Kovalev ◽  
Yu. I. Ryabkov ◽  
V. V. Viktorov
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Multiwalled Carbon Nanotubes ◽  
Defect Structure ◽  
Multiwalled Carbon

Raman spectroscopy of polystyrene nanofibers—Multiwalled carbon nanotubes composites

2013 ◽  
Vol 275 ◽  
pp. 23-27 ◽  
Author(s):  
Dorina M. Chipara ◽  
Javier Macossay ◽  
Ana V.R. Ybarra ◽  
A.C. Chipara ◽  
Thomas M. Eubanks ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Multiwalled Carbon Nanotubes ◽  
Multiwalled Carbon

DISPERSITY AND STABILITY MEASUREMENT OF FUNCTIONALIZED MULTIWALLED CARBON NANOTUBES IN ALCOHOLS

2008 ◽  
Vol 22 (25) ◽  
pp. 2493-2501 ◽  
Author(s):  
HUN-SIK KIM ◽  
MINSUNG KANG ◽  
WON-IL PARK ◽  
DON-YOUNG KIM ◽  
HYOUNG-JOON JIN
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Multiwalled Carbon ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Stability Measurement ◽  
The Stability

Multiwalled carbon nanotubes (MWCNTs) were dispersed in various alcohols such as methanol, ethanol and isopropanol using ultrasonication. In order to disperse the MWCNTs in the alcohols, they were treated using a mixture of H 2 SO 4 and HNO 3 (3 : 1, vol/vol). The concentration of MWCNTs was approximately 0.03 wt.% and they formed a homogeneous dispersion in the alcohol solutions. The functional groups introduced on the surface of the MWCNTs during the acid treatment were characterized by Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy. The dispersibility of the MWCNTs in the alcohols was characterized using atomic force microscopy, scanning electron microscopy and transmission electron microscopy. The stability of the MWCNT dispersions was also measured using a recently developed optical analyzer (Turbiscan).

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