scholarly journals Structural and Infrared Spectroscopy of Polyvinylpyrrolidone/Multi-walled Carbon Nanotubes Nanocomposite

2021 ◽  
Vol 19 (51) ◽  
pp. 1-6
Author(s):  
Shahad M. Omran ◽  
Estabraq T. Abdullah ◽  
Omar A. Al-Zuhairi
Keyword(s):  
Carbon Nanotubes ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
Bending Vibration ◽  
Ftir Studies ◽  
Uniform Dispersion ◽  
Intensity Changes ◽  
Multi Walled Carbon Nanotubes ◽  
P Type ◽  
Walled Carbon Nanotubes

In this work, polyvinylpyrrolidone (PVP)/ Multi-walled carbon nanotubes (MWCNTs) nanocomposites were prepared with two concentrations of MWCNTs by casting method. Morphological, structural characteristics and electrical properties were investigated. The state of MWCNTs dispersion in a PVP matrix was indicated by Field Effect-Scanning Electron Microscopy (FESEM) which showed a uniform dispersion of MWCNTs within the PVP matrix. X-ray Diffraction (XRD) indicate strong bonding of carbonyl groups of PVP composite chains with MWCNTs. Fourier transfer infrared (FTIR) studies shows characteristics of various stretching and bending vibration bands, as well as shifts in some band locations and intensity changes in others. Hall effect was studied to test the type of charge carriers which was shown to be P-type. The electrical conductivity was shown increased for the pure PVP and pure MWCNT from (2.047×10-5) (Ω.cm)-1 and (3.683×101) (Ω.cm)-1 to (2.51×102 and 2.36×102) (Ω.cm)-1for both concentrations of nanocomposites, which indicate the conductivity was enhancement by using the carbon nanotubes.

Two-step synthesis of polyurethane/multi-walled carbon nanotubes polymer composite to achieve high percentage particle reinforcement for mechanical applications

2021 ◽  
pp. 002199832199945
Author(s):  
Dinesh Kumar ◽  
Suneev Anil Bansal ◽  
Navin Kumar ◽  
Prashant Jindal
Keyword(s):  
Carbon Nanotubes ◽  
Synthesis Method ◽  
Step Method ◽  
Molding Method ◽  
Uniform Dispersion ◽  
Noticeable Improvement ◽  
Multi Walled Carbon Nanotubes ◽  
Mixing Method ◽  
Compressive Testing ◽  
Walled Carbon Nanotubes

The present work has been aimed to synthesize Polyurethane (PU)/Multi-Walled Carbon Nanotubes (MWCNTs) composite using a two-step method to enhance mechanical properties. In the first step, films (0.2 mm thickness) have been synthesized using a solution mixing method to disperse MWCNTs in the PU matrix. In the second step, thin films of uniformly dispersed MWCNTs in the PU matrix have been compression molded to synthesize PU/MWCNTs composite required for real mechanical applications. The two-step method has the advantages of solution mixing as well as compression molding method. The results of quasi-static nanoindentation tests indicated that in comparison to pure PU, elastic modulus and hardness have been enhanced by 124% and 53% respectively for 10 wt% PU/MWCNTs composite. Fracture resistance of PU/MWCNTs composites, with 7 wt% of MWCNTs, has been enhanced by 52% as compared to pure PU. To understand bulk behavior, nanoindentation results have been cross-verified with compression testing. Results of compressive testing shown that the modulus of composite material has been significantly improved under the influence of the increasing composition of MWCNTs. A noticeable improvement of 52% has been observed in compressive modulus of 10 wt% composite in equivalence to pure PU. The overall improvement in mechanical behavior has been attributed to the uniform dispersion of MWCNTs in the PU matrix by the two-step synthesis method.

scholarly journals Optimization of sulfate removal from wastewater using magnetic multi-walled carbon nanotubes by response surface methodology

2017 ◽  
Vol 76 (10) ◽  
pp. 2593-2602 ◽  
Author(s):  
Vahid Alimohammadi ◽  
Mehdi Sedighi ◽  
Ehsan Jabbari
Keyword(s):  
Carbon Nanotubes ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Polynomial Equation ◽  
X Ray Diffraction ◽  
Adsorption Models ◽  
Sulfate Removal ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Abstract This paper reports a facile method for removal of sulfate from wastewater by magnetic multi-walled carbon nanotubes (MMWCNTs). Multi-walled carbon nanotubes and MMWCNTs were characterized by X-ray diffraction, Raman, transmission electron microscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. The results of the analysis indicated that MMWCNTs were synthesized successfully. The MMWCNTs can be easily manipulated in a magnetic field for the desired separation, leading to the removal of sulfate from wastewater. Response surface methodology (RSM) coupled with central composite design was applied to evaluate the effects of D/C (adsorbent dosage per initial concentration of pollutant (mgadsorbent/(mg/l)initial)) and pH on sulfate removal (%). Using RSM methodology, a quadratic polynomial equation was obtained, for removal of sulfate, by multiple regression analysis. The optimum combination for maximum sulfate removal of 93.28% was pH = 5.96 and D/C = 24.35. The experimental data were evaluated by the Langmuir and Freundlich adsorption models. The adsorption capacity of sulfate in the studied concentration range was 56.94 (mg/g). It was found out that the MMWCNTs could be considered as a promising adsorbent for the removal of sulfate from wastewater.

Dispersion of Multi-Walled Carbon Nanotubes in Portland Cement Concrete Using Ultra-Sonication and Polycarboxylic Based Superplasticizer

2015 ◽  
Vol 802 ◽  
pp. 112-117 ◽  
Author(s):  
Ali Yousefi ◽  
Norazura Muhamad Bunnori ◽  
Mehrnoush Khavarian ◽  
Taksiah A. Majid
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Portland Cement ◽  
Cement Matrix ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Uniform Dispersion ◽  
Multi Walled Carbon Nanotubes ◽  
Sonication Technique ◽  
Walled Carbon Nanotubes

The potential properties of carbon nanotube-cement based materials strongly depend on the dispersion of carbon nanotubes (CNTs) within the cement matrix and the bonding between CNTs and the hydrated cement. The homogeneous dispersion of CNTs in the cement matrix yet is one of the main challenges due to strong van der Waals forces between nanotubes. In this study, a polycarboxylic ether based superplasticizer and ultra-sonication technique was used for dispersion of multi-walled carbon nanotubes (MWCNTs). Portland cement concrete specimens with different concentrations of MWCNTs (0.04 and 0.1 % by the weight of cement), with and without the presence of superplasticizer were investigated. Compressive strength test results revealed a significant improvement in mechanical properties of sample containing 0.1 % MWCNTs and 0.2 % superplasticizer. Moreover, field emission scanning electron microscopy (FESEM) images of fractured surfaces of hardened specimens showed a good dispersion of MWCNTs within the cement matrix. This method was developed to facilitate the uniform dispersion of MWCNTs in the cementitious concrete for better reinforcement in nanoscale and mechanical properties enhancement by transfer of load between the nanotubes and matrix.

Synthesis and Characterization of Nitrogen Doped Carbon Nanotubes

2010 ◽  
Vol 636-637 ◽  
pp. 714-721 ◽  
Author(s):  
K. Kordatos ◽  
A. Ntziouni ◽  
A. Theodoratou ◽  
Maria Perraki ◽  
M. Terrones ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Production Method ◽  
X Ray Diffraction ◽  
Nitrogen Doped ◽  
Solid Mixture ◽  
Multi Walled Carbon Nanotubes ◽  
Metallic Catalyst ◽  
Nitrogen Doped Carbon ◽  
Walled Carbon Nanotubes

The present work describes the synthesis of nitrogen doped multi-walled carbon nanotubes (CNx CNT). The chosen production method was the catalytic pyrolysis of a solid mixture containing [Ni(DMG)2] and melamine (C3H6N6), under an Αr atmosphere. A series of various experiments were performed, using different proportions of the reaction mixture, in order to optimize the production conditions of nitrogen doped carbon nanotubes. Finally, the produced materials were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), Raman spectroscopy as well as thermogravimetric analysis (TGA). The obtained data from all the above analyses, showed the formation of nitrogen doped carbon nanotubes of various diameters as well as nanofibers surrounded by byproducts such as aggregations of amorphous carbon and metallic catalyst, depending on the proportion of the reaction mixture.

scholarly journals Gas-sensitive properties of individual carbon nanotubes modified by ion and electron irradiation

2020 ◽  
pp. 89-93
Author(s):  
N. A. Davletkildeev ◽  
Keyword(s):  
Carbon Nanotubes ◽  
Electron Irradiation ◽  
Gas Sensitivity ◽  
Resistance Change ◽  
Type Conductivity ◽  
Nitrogen Doped ◽  
Multi Walled Carbon Nanotubes ◽  
Argon Ions ◽  
P Type ◽  
Walled Carbon Nanotubes

The time characteristics of resistance change of individual nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs), initial and irradiated with electrons, protons and argon ions has been measured upon exposure to ammonia and nitrogen dioxide. It is found that the initial N-MWCNTs have n-type conductivity, N-MWCNTs irradiated with protons and argon ions have p-type conductivity, and those irradiated with electrons have n-type conductivity. The relative gas sensitivity of individual N-MWCNTs, initial and irradiated with ions and electrons, has been determined

scholarly journals Uniform Dispersion and Exfoliation of Multi-Walled Carbon Nanotubes in CNT-MgB2 Superconductor Composites Using Surfactants

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3044
Author(s):  
Mohammed Shahabuddin ◽  
Niyaz Ahamad Madhar ◽  
Nasser S. Alzayed ◽  
Mohammad Asif
Keyword(s):  
Carbon Nanotubes ◽  
Colloidal Suspension ◽  
Direct Synthesis ◽  
Cost Effective ◽  
Heat Processing ◽  
Synthesis Route ◽  
Uniform Dispersion ◽  
Multi Walled Carbon Nanotubes ◽  
Magnetic Resonance Imaging Mri ◽  
Walled Carbon Nanotubes

We developed a novel yet commercially viable strategy of synthesizing superior high-TC superconducting composites by dispersing fully exfoliated carbon nanotubes (CNTs) uniformly throughout the grain of CNT-MgB2 composites. First, we optimized the amount of the surfactant required to produce a highly stable and homogeneous colloidal suspension of CNTs. This amount was found to be 1/8th of the amount of CNTs. Second, we prepared a homogeneous CNT-B mixture by adding amorphous nano-boron (B) to the colloidal CNT suspension. Next, two different MgB2 synthesis routes were explored. In one case, we mixed an appropriate amount of Mg in the CNT-B mixture and carried out sintering. In the second case, the CNT-B mixture was heat treated at 500 °C, prior to mixing with Mg and sintering to form CNT-MgB2. Both kinds of samples were rigorously characterized to obtain an insight into their properties. The direct synthesis route shows a clear exfoliation and uniform dispersion of CNTs with a critical current density (JC) of 104 A/cm2 at 3.5 T and 20 K, which is useful for the application in magnetic resonance imaging MRI magnet operating with a cryogen free cooler. Our JC(H) result is 10 times higher than that of the pure sample. By contrast, the performance of the sample subjected to heat processing before sintering was severely compromised given the formation of MgO. Despite its simplicity, the direct synthesis route can be used for the cost-effective fabrication of CNT–MgB2 superconducting composites.

scholarly journals Load Sensing Capability of Cementitious Matrixes—Nanomodified Cement Versus Carbon Nanotube Dispersion

Proceedings ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 19
Author(s):  
Buasiri ◽  
Habermehl-Cwirzen ◽  
Krzeminski ◽  
Cwirzen
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Properties ◽  
Carbon Nanomaterials ◽  
Compressive Load ◽  
Weight Changes ◽  
Load Sensing ◽  
Carbon Nanotube Dispersion ◽  
Uniform Dispersion ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

A cement-based matrix incorporating conductive materials such as carbon nanotubes and carbon nanofibers can have self-sensing capability. Both nanomaterials are characterized by excellent physical, mechanical and electrical properties. A disadvantage is that due to their hydrophobic nature it is very difficult to ensure uniform dispersion throughout the cementitious matrix. To overcome this problem a new nanomodified cement containing in-situ attached CNFs was developed leading to a very homogenous and conductive binder matrix. This study aimed to compare the piezoresistive responses of two types of matrixes, one based on the nanomodified cement and the second containing multi-walled carbon nanotubes. Several mortars were prepared containing either MWCNTs or the nanomodified cement, which partially replaced the untreated cement. The effective amount of the carbon nanomaterials was the same for both types of mixes and ranged from 0 wt.% to 0.271 wt.%, calculated by the all binder weight. Changes in the electrical properties were determined while applying compressive load. The results showed that the binders based on the nanomodified cement have significantly better load sensing capabilities and are suitable for applications in monitoring systems.

scholarly journals Negatively-Doped Single-Walled Carbon Nanotubes Decorated with Carbon Dots for Highly Selective NO2 Detection

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2509
Author(s):  
Namsoo Lim ◽  
Jae-Sung Lee ◽  
Young Tae Byun
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensors ◽  
Cost Effective ◽  
Single Walled Carbon Nanotubes ◽  
X Ray Diffraction ◽  
Single Walled Carbon ◽  
Sensor Applications ◽  
Transmission Electron ◽  
P Type ◽  
Walled Carbon Nanotubes

In this study, we demonstrated a highly selective chemiresistive-type NO2 gas sensor using facilely prepared carbon dot (CD)-decorated single-walled carbon nanotubes (SWCNTs). The CD-decorated SWCNT suspension was characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-visible spectroscopy, and then spread onto an SiO2/Si substrate by a simple and cost-effective spray-printing method. Interestingly, the resistance of our sensor increased upon exposure to NO2 gas, which was contrary to findings previously reported for SWCNT-based NO2 gas sensors. This is because SWCNTs are strongly doped by the electron-rich CDs to change the polarity from p-type to n-type. In addition, the CDs to SWCNTs ratio in the active suspension was critical in determining the response values of gas sensors; here, the 2:1 device showed the highest value of 42.0% in a sensing test using 4.5 ppm NO2 gas. Furthermore, the sensor selectively responded to NO2 gas (response ~15%), and to other gases very faintly (NO, response ~1%) or not at all (CO, C6H6, and C7H8). We propose a reasonable mechanism of the CD-decorated SWCNT-based sensor for NO2 sensing, and expect that our results can be combined with those of other researches to improve various device performances, as well as for NO2 sensor applications.

The Impact of Nanomaterials on Fabrication Silicon Solar Cells by Pulsed Laser Deposition

2020 ◽  
Vol 30 ◽  
pp. 41-54
Author(s):  
Shelan A. Farman ◽  
Muayed K. Ibrahim ◽  
Kadhim A. Aadim
Keyword(s):  
Carbon Nanotubes ◽  
Solar Cells ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
Atomic Force ◽  
Si Solar Cells ◽  
Multi Walled Carbon Nanotubes ◽  
Uv Visible ◽  
Walled Carbon Nanotubes ◽  
The Impact

Nanocarbon structures such as graphene (GR), single-walled carbon nanotubes (SWCNTs) as well as the multi-walled carbon nanotubes (MWCNTs) were deposited on crystalline n-type silicon wafers to fabricate nanoCarbon-Si solar cells. Nanocarbon films deposited on glass and porous silicon (PS) via pulse laser deposition (PLD) with the use of Q-Switching Nd: YAG laser with λ=1064 (nm), Energy (E)=700 (mJ), Repetition rate (f)=6 (HZ) under vacuum condition with 2.5×10-2 (mbar). The surface morphology, structure, and optical Nanocarbon thin films have been examined with the use of X-ray Diffraction (XRD), Atomic force microscope (AFM), FTIR spectrophotometer and UV-visible. In addition, the power conversion efficiency that is related to the prepared solar cells is estimated through J-V characterization. The PCE of all Nanocarbon/PS follows the orders; SWCNTs/PS < MWCNTs/PS< GR/PS.

Simulation and experimental investigation of multi-walled carbon nanotubes/aluminum composite fabrication using friction stir processing

2021 ◽  
pp. 095440892110340
Author(s):  
Mostafa Akbari ◽  
Parviz Asadi
Keyword(s):  
Carbon Nanotubes ◽  
Wear Resistance ◽  
Friction Stir Processing ◽  
Particle Distribution ◽  
Base Alloy ◽  
Stir Zone ◽  
Friction Stir ◽  
Uniform Dispersion ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotube/aluminum composites are fabricated on Al–Si cast alloy employing friction stir processing. First, the microstructure of the stir zone, as well as the effect of process parameters on the size of silicon particles, is investigated. Then, the process is numerically simulated using a thermo-mechanically coupled three-dimensional finite element method model. Material flow, as the primary reason for the dispersion of reinforcing particles, is considered in the numerical model, and proper conditions to obtain a uniform dispersion of multi-walled carbon nanotubes are determined. Scanning electron microscope analysis is carried out to consider the particle distribution in the texture of the stir zone. The results show that the particle distribution improves significantly by changing the tool rotation direction between the friction stir processing passes. The hardness test is accomplished on the cross-section of the friction stir processed specimens, and finally, the wear test is performed to compare the wear resistance of the composites with the base alloy. The results show that the wear resistance and hardness of the produced composites are considerably enhanced compared to the base alloy.

Sign in / Sign up

Export Citation Format

Share Document