Effects of Reflux Temperature and Molarity of Acidic Solution on Chemical Functionalization of Helical Carbon Nanotubes

2017 ◽  
Vol 11 (1) ◽  
Author(s):  
Sean Taklimi ◽  
Ali Ghazinezami ◽  
Kim Cluff PhD ◽  
Davood Askari
Keyword(s):  
Carbon Nanotubes ◽  
Acidic Solution ◽  
Chemical Functionalization ◽  
Helical Carbon Nanotubes ◽  
Reflux Temperature

scholarly journals Chemical Functionalization of Helical Carbon Nanotubes: Influence of Sonication Time and Concentrations of Sulfuric and Nitric Acids with 3 : 1 Mixing Ratio

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Sean R. Taklimi ◽  
Ali Ghazinezami ◽  
Davood Askari
Keyword(s):  
Carbon Nanotubes ◽  
Process Parameters ◽  
High Performance ◽  
Mixing Ratio ◽  
Sonication Time ◽  
Polymeric Nanocomposites ◽  
Chemical Functionalization ◽  
Helical Carbon Nanotubes ◽  
Uniform Dispersion ◽  
Dispersion Test

Carbon nanotubes (CNTs) with straight geometries have been widely studied for various engineering applications, and they are often treated or functionalized to improve their effectiveness, depending on their role and expected performance. However, helical configurations of CNTs (HCNTs) have not been sufficiently investigated, especially in their functionalized states for high-performance nanocomposite applications. The coil-shaped geometry of these HCNTs increases the mechanical entanglement of these nanotubes with a host resin system when they are used as reinforcements. This consequently has the potential to improve the mechanical, thermal, electrical, and magnetic properties of the polymeric matrix systems. A uniform dispersion of CNTs in the resin plays an important role in obtaining improved and consistent properties in the final nanocomposite part. To improve the homogeneous dispersion (individual suspension) of these nanotubes in the host resin and to enhance their interactions/bonds with the resin molecules, the surface of these nanotubes should be modified. This study investigates a sonication method for chemical functionalization of HCNTs using a mixture of sulfuric and nitric acids with 3 to 1 mixing ratio [3 : 1], and it evaluates the effects of acid concentrations and sonication time on the severity of the functionalization process. To evaluate the effectiveness of the process parameters, the functionalized HCNTs (FHCNTs) were examined using several characterization instruments and techniques such as Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), X-ray Diffraction (XRD), visual dispersion test, and Raman spectroscopy. The characterization results confirmed that the changes in process parameters were mostly effective and the atomic structures of the functionalized HCNTs were successfully altered. All FHCNT samples demonstrated higher dispersion uniformity, increase in Raman ID/IG ratios, and changes in the FTIR spectra compared to the pristine HCNTs. Most of the FHCNTs had a reduction in crystallinity, which was consistent with our expectation that functionalization generates more defects on the surface structure of HCNTs, thus leading to a lower intensity of the graphitic peak. The largest reduction in crystallinity was seen for HCNTs treated with a 16 molarity acidic solution; therefore, the HCNTs that were treated with lower molarity acids could be used for further studies and explored for their effective applications in improving the mechanical, thermal, and electrical properties of polymeric nanocomposites.

scholarly journals Fracture toughness of one- and two-dimensional nanoreinforced cement via scratch testing

2021 ◽  
Vol 379 (2203) ◽  
pp. 20200288 ◽  
Author(s):  
Ange-Therese Akono
Keyword(s):  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Cement Industry ◽  
Vertical Force ◽  
Two Dimensional ◽  
Scratch Testing ◽  
Helical Carbon Nanotubes ◽  
Reinforced Cement ◽  
Carbon Based Nanomaterials ◽  
Carbon Based

Cement is the most widely consumed material globally, with the cement industry accounting for 8% of human-caused greenhouse gas emissions. Aiming for cement composites with a reduced carbon footprint, this study investigates the potential of nanomaterials to improve mechanical characteristics. An important question is to increase the fraction of carbon-based nanomaterials within cement matrices while controlling the microstructure and enhancing the mechanical performance. Specifically, this study investigates the fracture response of Portland cement reinforced with one- and two-dimensional carbon-based nanomaterials, such as carbon nanofibres, multiwalled carbon nanotubes, helical carbon nanotubes and graphene oxide nanoplatelets. Novel processing routes are shown to incorporate 0.1–0.5 wt% of nanomaterials into cement using a quadratic distribution of ultrasonic energy. Scratch testing is used to probe the fracture response by pushing a sphero-conical probe against the surface of the material under a linearly increasing vertical force. Fracture toughness is then computed using a nonlinear fracture mechanics model. Nanomaterials are shown to bridge nanoscale air voids, leading to pore refinement, and a decrease in the porosity and the water absorption. An improvement in fracture toughness is observed in cement nanocomposites, with a positive correlation between the fracture toughness and the mass fraction of nanofiller for graphene-reinforced cement. Moreover, for graphene-reinforced cement, the fracture toughness values are in the range of 0.701 to 0.717 MPa m . Thus, this study illustrates the potential of nanomaterials to toughen cement while improving the microstructure and water resistance properties. This article is part of a discussion meeting issue ‘A cracking approach to inventing new tough materials: fracture stranger than friction’.

scholarly journals Synthesis, Characterization and Study of DC Electrical Conductivity of Poly[MWCNT/Imidoselenium] Composite

2019 ◽  
Author(s):  
Abeer O. Obeid ◽  
Fatma Al-Yusufy ◽  
Sama A Al-Aghbari ◽  
omar alshujaa ◽  
Yassin Gaber ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Selenium Dioxide ◽  
Chemical Functionalization ◽  
Dc Electrical Conductivity ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

<p>The chemical functionalization of amino multi-walled carbon nanotubes (MWCNT-NH<sub>2</sub>) by selenium dioxide (SeO<sub>2</sub>) was used to produce Poly [MWCNT/Imidoselenium] composite. The prepared poly-composite was characterized by FTIR, SEM, TEM, XRD, UV, DSC and TGA. The DC electrical conductivity of poly-composite was 4.3×10<sup>-4</sup> S/cm due to the interaction between the nanotubes. </p>

Effect of the Chemical Functionalization on Charge Transport in Carbon Nanotubes at the Mesoscopic Scale

Nano Letters ◽  
2009 ◽  
Vol 9 (3) ◽  
pp. 940-944 ◽  
Author(s):  
Alejandro López-Bezanilla ◽  
François Triozon ◽  
Sylvain Latil ◽  
X. Blase ◽  
Stephan Roche
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transport ◽  
Mesoscopic Scale ◽  
Chemical Functionalization

scholarly journals Narrowing Segments of Helical Carbon Nanotubes with Curved Aromatic Panels

2019 ◽  
Vol 58 (22) ◽  
pp. 7385-7389 ◽  
Author(s):  
Kanako Kogashi ◽  
Taisuke Matsuno ◽  
Sota Sato ◽  
Hiroyuki Isobe
Keyword(s):  
Carbon Nanotubes ◽  
Helical Carbon Nanotubes
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