Improved Functionalization of Multiwalled Carbon Nanotubes in Ultra-Low Acid Volume: Effect of Solid/Liquid Interface

Castro, Vinícius G. de; Costa, Ingrid B.; Medeiros, Felipe da Silva; Siqueira, Éder José; Kasama, Alexander H.; Figueiredo, Kátia Cecília de Souza; Lavall, Rodrigo L.; Silva, Glaura G.

doi:10.21577/0103-5053.20190166

Cited by 10 publications

(9 citation statements)

References 49 publications

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“…This peculiarity is a direct consequence of the covalent functionalization carried out on the carbon nanotubes. In this regard, it should be noted that the covalent functionalization acts above all in the areas where the carbon nanofiller has more defects associated with amorphous carbon originated from the MWCNTs synthesis, thus leading to a modification of MWCNT structural quality linked to the aspect ratio, or the length-to-diameter ratio [ 34 , 45 ].…”

Section: Resultsmentioning

confidence: 99%

Tunneling Atomic Force Microscopy Analysis of Supramolecular Self-Responsive Nanocomposites

et al. 2021

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A big step forward for composite application in the sector of structural materials is given by the use of Multi-Wall Carbon Nanotubes (MWCNTs) functionalized with hydrogen bonding moieties, such as barbiturate and thymine, to activate self-healing mechanisms and integrate additional functionalities. These materials with multiple healing properties at the same damaged site, imparted by hydrogen bonds, will also have the potential to improve material reliability, extend the service life, reduce replacement costs, and improve product safety. This revolutionary approach is obtained by integrating the non-covalent interactions coupled with the conventional covalent approach used to cross-link the polymer. The objective of this work is to characterize rubber-toughened supramolecular self-healing epoxy formulations based on unfunctionalized and functionalized MWCNTs using Tunneling Atomic Force Microscopy (TUNA). This advanced technique clearly shows the effect produced by the hydrogen bonding moieties acting as reversible healing elements by their simultaneous donor and acceptor character, and covalently linked to MWCNTs to originate self-healing nanocomposites. In particular, TUNA proved to be very effective for the morphology study of both the unfunctionalized and functionalized carbon nanotube-based conductive networks, thus providing useful insights aimed at understanding the influence of the intrinsic nature of the nanocharge on the final properties of the multifunctional composites.

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Section: Resultsmentioning

confidence: 99%

Tunneling Atomic Force Microscopy Analysis of Supramolecular Self-Responsive Nanocomposites

et al. 2021

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“…They have an average diameter and average length of 20 nm and 4.5 μm respectively. As described by Castro et al, [ 18 ] the MWCNTs were functionalized in a process carried out with a solution of 3:1 in volume of H 2 SO 4 /HNO 3. The best conditions for functionalization of the MWCNTs was found at 70°C for 20 min.…”

Section: Methodsmentioning

confidence: 99%

“…[14][15][16][17] The dispersion of nano reinforcements in the matrix, in order to obtain cluster-free mixtures, and a good strength between the nanofiller and epoxy interfaces are the main factors that affect the performance of nanocomposite adhesives. [1,4,18] Other aspects that influence adhesive performance are the thickness of the adherent, the roughness of the surface adherent, the thickness of the bond line and the wettability of the adhesive over the surface where it is applied. [1,5,6] According to Nascimento et al, [7] it is expected that adhesive joints are strongly influenced by environmental conditions causing a considerable amount of adhesive failures.…”

Section: Introductionmentioning

confidence: 99%

Investigation of effects of extreme environment conditions on multiwall carbon nanotube‐epoxy adhesive and adhesive joints

et al. 2022

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Mechanical and thermal properties of epoxy‐multiwall carbon nanotubes (MWCNTs) at different fractions (0.0, 0.25, 0.5, and 1.0 wt%) were investigated. The dispersion of the nanotubes in an epoxy adhesive commonly used in an automotive application was performed using a grease worker. This device has a perforated plate, able to produce mechanical shear. To investigate the behavior of adhesive‐carbon nanotubes mixtures and the bonding performance, four groups were prepared using two different perforated plates, P1 and P2. All MWCNT‐epoxy were submitted to extreme environmental conditions, resumed as reference (non‐aged), 500 h at 100°C, 500 h at 95% of relative humidity at 40°C, and 500 h under salt spray. A reduction in glass transition temperature was observed with the addition of the nanofiller and no increases on statistic heat‐resistant index temperature were noticed in MWCNT‐epoxy produced using both plates. Changes in the peaks at 3300, 1510, and 835 cm−1 after aging were seen in infrared spectra. The MWCNT addition to pure epoxy increased the apparent shear strength by 14% using P1. In P2, which has the mechanical shear greater by a factor of 2, no significant differences were observed, due to defects and agglomeration of MWCNTs observed by image analysis.

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“…Graphene oxide (GO), CNToxidized (CNTO), GO functionalized with triethylenetetramine (TETA) and CNTO functionalized with TETA (CNTOA) were obtained by previous routes [15], [16] and studied at the Center for Nanotechnology of Nanomaterials and Graphene (CTNano) -Brazil. Table 1 shows the main properties of the carbon nanomaterials produced at CTNano and fully characterized in our previous works [17][18] and in this work.…”

Section: Methodsmentioning

confidence: 99%

Hydrogels Based on Polyacrylamide and Functionalized Carbon Nanomaterials for Adsorption of a Cationic Dye

Silveira

Caliman²,

Silva³

2022

J Polym Environ

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Malachite green (MG) is used for the dyeing of cotton, paper, and jute, among other materials, and presents acute toxicity to a wide range of aquatic and terrestrial animals. A polyacrylamide (PA) hydrogel modi ed with a low content of oxygenated and aminated carbon nanomaterials may be a suitable candidate to adsorb MG from wastewater. Herein, modi ed graphene and carbon nanotubes (CNTs) were incorporated during the in situ polymerization of PAM. The swelling and adsorption capacity were investigated to explore the in uences of different carbon dimensionalities (1D and 2D), zeta potentials and nano ller concentrations on the adsorption behavior of the hydrogel. There was an increase of approximately 1,500% in the adsorption capacity after 24 h of exposure of a hydrogel with graphene oxide (GO) at 0.25 wt% with respect to the neat PA. Aminated graphene produced similar gains in the adsorption capacity of the GO-hydrogel, although it presents a positive zeta potential that is the opposite of that of GO. The modi ed CNTs showed smaller gains in the adsorption capacity, reaching a maximum 400% increase with respect to the PA hydrogel. The main factors that seem to affect the adsorption capacity were the dimensionality and degree of functionalization. The graphene-based nano llers were 3 to 4 times more functionalized than the nanotubes. The adsorption results were adjusted with a pseudosecond order kinetic model that allowed a complementary discussion about the nature of the physicochemical effects on the process of MG adsorption in the hydrogel nanocomposites.

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Improved Functionalization of Multiwalled Carbon Nanotubes in Ultra-Low Acid Volume: Effect of Solid/Liquid Interface

Cited by 10 publications

References 49 publications

Tunneling Atomic Force Microscopy Analysis of Supramolecular Self-Responsive Nanocomposites

Tunneling Atomic Force Microscopy Analysis of Supramolecular Self-Responsive Nanocomposites

Investigation of effects of extreme environment conditions on multiwall carbon nanotube‐epoxy adhesive and adhesive joints

Hydrogels Based on Polyacrylamide and Functionalized Carbon Nanomaterials for Adsorption of a Cationic Dye

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