scholarly journals Additive-free carbon nanotube dispersions, pastes, gels, and doughs in cresols

2018 ◽  
Vol 115 (22) ◽  
pp. 5703-5708 ◽  
Author(s):  
Kevin Chiou ◽  
Segi Byun ◽  
Jaemyung Kim ◽  
Jiaxing Huang
Keyword(s):  
Carbon Nanotubes ◽  
Form Factors ◽  
Weight Percent ◽  
Liquid Mixtures ◽  
Free Standing ◽  
Continuous Transition ◽  
Dispersing Agent ◽  
Disperse Carbon ◽  
Broad Array ◽  
High Concentrations

Cresols are a group of naturally occurring and massively produced methylphenols with broad use in the chemical industry. Here, we report that m-cresol and its liquid mixtures with other isomers are surprisingly good solvents for processing carbon nanotubes. They can disperse carbon nanotubes of various types at unprecedentedly high concentrations of tens of weight percent, without the need for any dispersing agent or additive. Cresols interact with carbon nanotubes by charge transfer through the phenolic hydroxyl proton and can be removed after processing by evaporation or washing, without altering the surface of carbon nanotubes. Cresol solvents render carbon nanotubes polymer-like rheological and viscoelastic properties and processability. As the concentration of nanotubes increases, a continuous transition of four states can be observed, including dilute dispersion, thick paste, free-standing gel, and eventually a kneadable, playdough-like material. As demonstrated with a few proofs of concept, cresols make powders of agglomerated carbon nanotubes immediately usable by a broad array of material-processing techniques to create desirable structures and form factors and make their polymer composites.

scholarly journals Thermoelectric Properties of Thin Films from Sorted Single-Walled Carbon Nanotubes

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3808 ◽  
Author(s):  
Blazej Podlesny ◽  
Bogumila Kumanek ◽  
Angana Borah ◽  
Ryohei Yamaguchi ◽  
Tomohiro Shiraki ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Thermoelectric Properties ◽  
Large Scale ◽  
Single Walled Carbon Nanotubes ◽  
Parent Material ◽  
Free Standing ◽  
Two Phase ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes ◽  
Aqueous Two Phase Extraction

Single-walled carbon nanotubes (SWCNTs) remain one of the most promising materials of our times. One of the goals is to implement semiconducting and metallic SWCNTs in photonics and microelectronics, respectively. In this work, we demonstrated how such materials could be obtained from the parent material by using the aqueous two-phase extraction method (ATPE) at a large scale. We also developed a dedicated process on how to harvest the SWCNTs from the polymer matrices used to form the biphasic system. The technique is beneficial as it isolates SWCNTs with high purity while simultaneously maintaining their surface intact. To validate the utility of the metallic and semiconducting SWCNTs obtained this way, we transformed them into thin free-standing films and characterized their thermoelectric properties.

Fatigue of a Nanocomposite Laminate

2008 ◽  
Author(s):  
Justin W. Wilkerson ◽  
Jiang Zhu ◽  
Daniel C. Davis
Keyword(s):  
Carbon Nanotubes ◽  
Polymer Nanocomposite ◽  
Weight Percent ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Carbon Fabric ◽  
Molding Process ◽  
Functionalized Carbon Nanotubes ◽  
Multi Scale ◽  
Reinforced Polymer

A multi-scale carbon fiber reinforced polymer nanocomposite laminate, with strategically incorporated fluorine functionalized carbon nanotubes at 0.2 weight percent, is studied for improvements in strength, stiffness and fatigue life under both tension-tension fatigue (R = +0.1) and tension-compression fatigue (R = −0.1) loading. The nanotubes were incorporated into the carbon fabric, and laminates were fabricated using a high temperature vacuum assisted resin transfer molding process. The influence of the fluorinated functionalized carbon nanotubes on the evolution of damage and the resistance to catastrophic failure is credited for these mechanical property improvements.

Mechanical Properties Of Polyaniline / Multi-walled Carbon Nanotube Composite Films

2003 ◽  
Vol 791 ◽  
Author(s):  
P. C. Ramamurthy ◽  
W. R. Harrell ◽  
R. V. Gregory ◽  
B. Sadanadan ◽  
A. M. Rao
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Composite Films ◽  
Weight Percent ◽  
Organic Electronic Devices ◽  
Multiwalled Carbon ◽  
Multi Walled Carbon Nanotube ◽  
Contact Devices ◽  
Carbon Nanotube Composite

ABSTRACTHigh molecular weight polyaniline / multi-walled carbon nanotube composite films were fabricated using solution processing. Composite films with various weight percentages of multiwalled carbon nanotubes were fabricated. Physical properties of these composites were analyzed by thermogravimetric analysis, tensile testing, and scanning electron microscopy. These results indicate that the addition of multiwalled nanotubes to polyaniline significantly enhances the mechanical properties of the films. In addition, metal–semiconductor (composite) (MS) contact devices were fabricated, and it was observed that the current level in the films increased with increasing multiwalled nanotube content. Furthermore, it was observed that polyaniline containing one weight percent of carbon nanotubes appears to be the most promising composition for applications in organic electronic devices.

Study on Electrochemical Hydrogen Storage of Multi-Walled Carbon Nanotubes

2007 ◽  
Vol 26-28 ◽  
pp. 831-834 ◽  
Author(s):  
Lei Xie ◽  
Xiao Qi Li
Keyword(s):  
Carbon Nanotubes ◽  
Hydrogen Storage ◽  
Storage Capacity ◽  
Weight Percent ◽  
Chemical Form ◽  
Hydrogen Storage Capacity ◽  
Electrochemical Hydrogen Storage ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Discharging Capacity

The electrode(Ni-MWNTs) containing nickel(Ni) and multi-walled carbon nanotubes (MWNTs) was prepared by composite electrodeposit. Electrochemical hydrogen storage of the electrode was studied. The result showed a high electrochemical discharging capacity of up to 1361.1mA·h·g-1, which corresponds to a hydrogen storage capacity of 4.77Wt%(weight percent). Test of cyclic lifespan showed MWNTs had certain cyclic lifespan. Cyclic voltammetry tests showed that MWNTs can store hydrogen in chemical form.

An integrated numerical–experimental study on the optimum utilization of carbon nanotubes in laminated composites

2016 ◽  
Vol 19 (2) ◽  
pp. 231-258 ◽  
Author(s):  
Mahmood Heshmati ◽  
Bandar Astinchap ◽  
Masoud Heshmati ◽  
Mohammad Hosein Yas ◽  
Yasser Amini
Keyword(s):  
Carbon Nanotubes ◽  
Natural Frequency ◽  
Experimental Studies ◽  
Distribution Patterns ◽  
Weight Percent ◽  
Composite Beams ◽  
Linear Distribution ◽  
Fundamental Natural Frequency ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this paper, a set of numerical and experimental studies are performed to improve mechanical and vibrational properties of carbon nanotubes-reinforced composites. First, at a design concept level, linear distribution patterns of multi-walled carbon nanotubes through the thickness of a typical beam is adopted to investigate its fundamental natural frequency for a given weight percent of multi-walled carbon nanotubes. Both Timoshenko and Euler-Bernoulli beam theories are used in the derivation of the governing equations. The finite element method is employed to obtain a numerical approximation of the motion equation. Next, based on the introduced distribution patterns, laminated multi-walled carbon nanotubes-reinforced polystyrene-amine composite beams are fabricated. Static and experimental modal tests are performed to measure the effective stiffness and fundamental natural frequencies of the fabricated composite beams. Also, in order to generate realistic model to investigate the material properties of fabricated composite beams, the actual tensile specimens of multi-walled carbon nanotubes/polystyrene-amine composites are successfully fabricated and the tensile behaviors of both pure matrix and composites are investigated. To better interfacial bonding between carbon nanotubes and polymer, a chemical treatment is performed on carbon nanotubes. It is seen that the addition of a few wt. % of multi-walled carbon nanotubes make considerable increase in the Young's modulus and the tensile strength of the composite. It is observed from the free vibration tests that the uniform distribution of multi-walled carbon nanotubes results in an increase of 9.5% in the fundamental natural frequency of the polymer cantilever beam, whereas using the symmetric multi-walled carbon nanotube distribution increased its fundamental natural frequency by 17.32%.

scholarly journals Multiwalled carbon nanotubes in alfalfa and wheat: toxicology and uptake

2012 ◽  
Vol 9 (77) ◽  
pp. 3514-3527 ◽  
Author(s):  
Pola Miralles ◽  
Errin Johnson ◽  
Tamara L. Church ◽  
Andrew T. Harris
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Root Elongation ◽  
Wheat Root ◽  
Root Tip ◽  
Multiwalled Carbon ◽  
Wheat Seedlings ◽  
Industrial Grade ◽  
High Concentrations ◽  
Multiwalled Cnts

Data on the bioavailability and toxicity of carbon nanotubes (CNTs) in the environment, and, in particular, on their interactions with vascular plants, are limited. We investigated the effects of industrial-grade multiwalled CNTs (75 wt% CNTs) and their impurities on alfalfa and wheat. Phytotoxicity assays were performed during both seed germination and seedling growth. The germinations of both species were tolerant of up to 2560 mg l −1 CNTs, and root elongation was enhanced in alfalfa and wheat seedlings exposed to CNTs. Remarkably, catalyst impurities also enhanced root elongation in alfalfa seedlings as well as wheat germination. Thus the impurities, not solely the CNTs, impacted the plants. CNT internalization by plants was investigated using electron microscopy and two-dimensional Raman mapping. The latter showed that CNTs were adsorbed onto the root surfaces of alfalfa and wheat without significant uptake or translocation. Electron microscopy investigations of internalization were inconclusive owing to poor contrast, so Fe 3 O 4 -functionalized CNTs were prepared and studied using energy-filter mapping of Fe 3 O 4 . CNTs bearing Fe 3 O 4 nanoparticles were detected in the epidermis of one wheat root tip only, suggesting that internalization was possible but unusual. Thus, alfalfa and wheat tolerated high concentrations of industrial-grade multiwalled CNTs, which adsorbed onto their roots but were rarely taken up.

The effects of diameter and chirality on the thermal transport in free-standing and supported carbon-nanotubes

2012 ◽  
Vol 100 (23) ◽  
pp. 233105 ◽  
Author(s):  
Bo Qiu ◽  
Yan Wang ◽  
Qing Zhao ◽  
Xiulin Ruan
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Transport ◽  
Free Standing

Porous polylactic acid/carbon nanotubes/polyaniline composite film as flexible free-standing electrode for supercapacitors

2019 ◽  
Vol 294 ◽  
pp. 312-324 ◽  
Author(s):  
Qi Wang ◽  
Hongxing Wang ◽  
Pengcheng Du ◽  
Juanli Liu ◽  
Dong Liu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Composite Film ◽  
Polylactic Acid ◽  
Free Standing

Conductivity of Graphene-Like Thin Films Prepared from Chemically Exfoliated Carbon Nanotubes (CNTs), Highly Oriented Pyrolytic Graphite (HOPG), Natural Flake Graphite, and Carbon Powder

2012 ◽  
Vol 1451 ◽  
pp. 125-130
Author(s):  
Matthew M. Marchese ◽  
Rosario A. Gerhardt
Keyword(s):  
Thin Films ◽  
Spin Coating ◽  
Average Pore Size ◽  
Pyrolytic Graphite ◽  
Chlorosulfonic Acid ◽  
Surfactant Solution ◽  
Carbon Powder ◽  
Free Standing ◽  
Average Pore ◽  
High Concentrations

ABSTRACTThe use of super acids such as chlorosulfonic acid (CSA) has proven to be extremely effective at exfoliating different forms of graphite in high concentrations without covalently functionalizing the surface of the graphene. Once quenched, the acid solutions can then be vacuum filtered through acid resistant polypropylene filter paper with an average pore size of 0.2 μm to collect the exfoliated carbon into a free standing retentate film. These films can then be easily washed, removed, and redispersed into solution by sonicating the films in a surfactant solution. Films were deposited onto various substrates using a range of spin coating parameters. This study has found that exfoliated CNTs provide the best conductivity out of the four types of chemically exfoliated carbon structures studied. CNTs have also proven to be the easiest type of exfoliated carbon to disperse and are able to stay in solution with less than 1%wt surfactant. The findings have shown that the electrical conductivity of the spin coated films actually increases with RPM and is inversely proportional to the film thickness. It is possible to achieve electrical conductivities as high as 10,507 ± 3728.64 [S/m] while still maintaining the transparency of the thin films. The initial spin coating step is more efficient at low ramp rates around 100 rpm/s and results in very smooth films. High spin speeds of 1800 rpm during the casting stage are found to play a large role in improving the conductivity of the films. Lastly, drying the samples on a hot plate for 5 min. on high has significantly improved the films electrical properties and virtually eliminated the need for tedious and expensive plasma cleaning treatments.

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