Search results for "OTU"

An Equivalent Orthotropic Representation of the Nonlinear Elastic Behavior of Multiwalled Carbon Nanotubes

2006

An equivalent orthotropic representation (EOR) of the nonlinear elastic behavior of multiwalled carbon nanotubes (MWCNTs) was developed based on a nested shell structural representation of MWCNTs. The EOR model was used together with the finite element method to simulate the large deformation of MWCNTs under bending, axial compression and radial compression. Results were compared with those of the nested shell model for four-, eight-, nine-, 14-, and 19-walled carbon nanotubes. The EOR model provides a dramatic improvement in computational efficiency and successfully quantitatively replicates the overall deformation behavior including the initial linear elastic behavior, the onset of local …

Development and Characterization of Novel Conductive Nanofiller Based on Multi-Walled Carbon Nanotubes Grafted with Poly(3,4-Ethylenedioxythiophene)

2018

In the present study, an approach for the graft polymerization of multi-walled carbon nanotubes (MWCNTs) with 3,4-ethylenedioxythiophene (EDOT) has been evaluated. The surface of the MWCNTs was activated with thiophene groups through the amide linker followed by oxidative polymerization of EDOT monomer resulted in the development of PEDOT-g-MWCNTs. The methods of thermal gravimetric analysis (TGA), X-ray fluorescence, and Raman spectroscopy were used for characterization of functionalization efficiency. The TGA data indicated of 21% functionalization attached to MWCNTs. X-ray fluorescence confirmed the presence of Cl, and S atoms in functionalized fillers. The study of Raman spectra confirm…

Water Adsorption Properties of Titanium(IV) Oxide Embedded in Multiwalled Carbon Nanotubes (CNT)

2019

Titanium(IV) oxide was embedded into carbon nanotubes through sonication. The water adsorption properties of the carbon nanotubes, titanium(IV) oxide and the titanium(IV) oxide embedded carbon nanotubes have been studied using near infrared spectroscopy and second derivative techniques. Each sample was evacuated, then exposed to 40% and 60% relative humidity to adsorb water molecules and the evolving adsorption near infrared spectra were studied. Adsorption properties were further studied by gravimetric analysis. Near infrared spectroscopic and Scanning Electron Microscopic studies confirm that the titanium(IV) oxide has been embedded into the carbon nanotube samples. The water adsorption p…

In-Situ Growth of Ultrathin Films of NiFe-LDHs: Towards a Hierarchical Synthesis of Bamboo-Like Carbon Nanotubes

2014

The synthesis of ultrathin films (UTFs) of NiFe-LDHs has been achieved by means of an in situ hydrothermal approach, leading to a flat disposition of the LDH crystallites on the substrate, in clear contrast to the most common perpendicular orientation reported to date. Experimental factors like time of synthesis or the nature of the substrate, seem to play a crucial role during the growing process. The 2D morphology of the NiFe-LDH crystallites was kept after a calcination procedure, leading to a topotactic transformation into mixed-metal oxide platelets. Hereby, in order to study the catalytic behavior of our samples, a chemical vapor deposition process is explored upon the as-synthesized …

Measurement of the surface resistivity and electrical conductivity of carbon nanotube sheets using the resonant post-method

2016

Abstract The dielectric post-resonant measurement method is extended to characterize the conduction properties of carbon nanotube sheets in the GHz frequency range ( 3 GHz f 20 GHz ) without the need for external contacts or the necessity of carbon coating. Three low-loss reference dielectrics ( TiO 2 , BaTi 4 O 9 , Teflon) with known dielectric properties are used. Conductivity values of various metals (steel, lead, brass, aluminium, copper) of the order 106–107 S/m were measured to show the suitability of the method. The electrical conductivity of the carbon nanotube sheets could be determined to approximately 1.7·105 S/m.

Cutting single-walled carbon nanotubes with an electron beam: evidence for atom migration inside nanotubes.

2006

Dispersions of Nanoclays of Different Shapes into Aqueous and Solid Biopolymeric Matrices. Extended Physicochemical Study

2010

Dispersions of nanofillers into aqueous and solid biopolymeric matrices were studied from the physicochemical viewpoint. This work was carried out based on the idea that the combination of biopolymers, derived from renewable resources, and nanofiller, environmentally friendly, may form a new generation of nanomaterials with excellent and unique properties at low cost. To this purpose, two pectins with different degrees of methyl esterification and nanoclays like halloysite and laponite RD were selected. The thermodynamic and structural studies on the aqueous mixtures of pectin and nanoclay were able to discriminate the interactions, which control the adsorption of pectin onto the filler and…

Parameters influencing the stiffness of composites reinforced by carbon nanotubes – A numerical–analytical approach

2014

Abstract Due to their high stiffness and strength, as well as their electrical conductivity, carbon nanotubes are under intense investigation as fillers in polymer matrix composites. The nature of the carbon nanotube/polymer bonding and the curvature of the carbon nanotubes may strongly reduce the reinforcing effect of the carbon nanotubes when added to a matrix to create composites. Here the effects of carbon nanotube waviness and the interaction with the matrix on the stiffness of the composite are investigated. Using a mixed numerical–analytical model, a parametric study of the waviness and volume fraction influence of CNTs on the elastic behavior of the nanocomposite is presented. The m…

Multifunctional properties of nanocomposites made by 1D and 2D graphene based fillers

2015

High aspect ratio graphene based fillers with different dimensionalities showed the ability to greatly modify rheological, mechanical, thermal and electrical properties of polymers at very low content. In this work, the effect of filler dimensionality on the multifunctional properties of an epoxy matrix reinforced by both carbon nanotubes (1D) and graphite nanoplatelets (2D) have been investigated across the percolation region. Keywords-- Carbon nanotube, Graphite nanoplatelet, nanocomposites, mechanical properties, ...

Impact of the inclusion of hydrotalcite on the morphological and electrical characteristics of an epoxy-based CNT nanocomposite

2012

The experimental results concerning the correlation between morphological and electrical characteristics of a MWCNT/epoxy based composites are presented. The impact of a nanoclay filler is investigated on the DC conductivity of a matrix loaded with different concentrations of MWCNT in order to evaluate the improvements on the dispersion of CNT inside the epoxy matrix. The dispersion is deemed to be very influencing on the electrical conductivity of the nanocomposite. A detailed morphological and structural characterization allows to interpret the electrical behaviour of the nanocomposites. © 2012 IEEE.