Experimental Investigation of Mechanical Behavior of Carbon-Nanotube Reinforced Cement Mortar

2011 ◽  
Vol 142 ◽  
pp. 217-220
Author(s):  
Li Wu Chang ◽  
Jin Chao Yue ◽  
Yu Zhou Sun
Keyword(s):  
Carbon Nanotube ◽  
Cement Mortar ◽  
Multiwall Carbon Nanotubes ◽  
Weight Ratio ◽  
Ultrasonic Energy ◽  
Reinforced Composites ◽  
Effective Dispersion ◽  
Optimum Weight ◽  
Reinforced Cement ◽  
Multiwall Carbon

In this study, effective dispersion of different amount of multiwall carbon nanotubes was achieved using a surfactant and in combination with the use of ultrasonic energy. The effects of surfactant and surfactant concentration on the plain cement mortar were investigated. Moreover, the mechanical behaviors of the carbon-nanotube reinforced composites were also analyzed. Experimental results indicate that the application of ultrasonic energy is absolutely necessary to produce a satisfactory dispersion of MWCNTs, and there exists an optimum weight ratio of surfactant to MWCNTs. It is found that the proper dispersion of MWCNTs can remarkably improve the flexural strength, compressive strength, and the toughness of the cement mortar composites.

scholarly journals Preparation and piezoresistivity of carbon nanotube-coated sand reinforced cement mortar

2020 ◽  
Vol 9 (1) ◽  
pp. 1445-1455
Author(s):  
Song Gao ◽  
Jianlin Luo ◽  
Jigang Zhang ◽  
Fei Teng ◽  
Chao Liu ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Cement Mortar ◽  
Aqueous Suspension ◽  
Ac Impedance ◽  
Stress Sensitivity ◽  
Multiwall Carbon Nanotube ◽  
Impedance Technique ◽  
Reinforced Cement ◽  
Coated Sand ◽  
Mechanical Strengths

Abstract Water and sand were used as the medium of multiwall carbon nanotube (MCNT) and prepared MCNT aqueous suspension and MCNT suspension-coated sand, respectively; afterwards, they were introduced into cement mortar (MNT/CM, MNTSM), respectively. Next, mechanical strengths and piezoresistive properties (DC resistivities (ρ v), AC impedances (Z r)) under cyclic loadings (σ c) of two types of MNT/CM and MNTSM nanocomposites were investigated to explore the intrinsic and self-sensing behaviors. Results reveal that MCNT can be evenly and well-coated on sand, which favors to achieve its intrinsic self-sensing property. Although the fraction changes in ρ v and Z r under the same σ c of MNTSM are both lower than those of MNT/CM, the stress sensitivity of MNTSM is only −1.16%/MPa (DC resistivity), −1.55%/MPa (AC impedance); its sensing linearity and stability (2.53, 2.45%; 2.73, 2.67%) are superior to those of MNT/CM (4.94, 2.57%; 3.78, 2.96%). Piezoresistivity using AC impedance technique is helpful to acquire balanced sensing sensitivity and stability while applied as intrinsic sensors in infrastructure.

Chemical vapor deposition of nickel-group metals on multiwall carbon nanotubes

2007 ◽  
Vol 85 (10) ◽  
pp. 645-650 ◽  
Author(s):  
Maoqi Feng ◽  
Richard J Puddephatt
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Carbon Nanotube ◽  
Low Temperature ◽  
Vapor Deposition ◽  
Multiwall Carbon Nanotubes ◽  
Chemical Vapor ◽  
Pt Films ◽  
Bimetallic Films ◽  
Multiwall Carbon

Chemical vapor deposition (CVD) of Ni, Pd, and Pt films and of Ni/Pd and Pd/Pt bimetallic films on multiwall carbon nanotubes (MWCNTs) can be effected at low temperature if the nanotubes are pretreated by CVD of titanium carbide. In the absence of the pretreatment, the CVD leads to formation of isolated nanoparticles of the nickel-group metals. The metallized MWCNTs are curved or kinked, as a result of the interaction with the metal. Preliminary oxidation of the carbon nanotubes allows easier metallization, and the bending of the metallated nanotubes is not observed in this case.Key words: Chemical vapor deposition, platinum, palladium, nickel, carbon, nanotube.

Role of Multiwall Carbon Nanotubes (MWCNT) on Electrical Conductivity of Polymer Composite as Alternative Materials for Bipolar Plate Fuel Cell

2013 ◽  
Vol 737 ◽  
pp. 183-190 ◽  
Author(s):  
Anne Zulfia ◽  
Sutopo ◽  
Bangkit Indriyana ◽  
M.E. Albar ◽  
S. Rohman
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Multiwall Carbon Nanotubes ◽  
Material Design ◽  
Bipolar Plate ◽  
Multiwall Carbon Nanotube ◽  
Crucial Component ◽  
Carbon Nano Tube ◽  
Multiwall Carbon

Polypropylene can be improved an electrical conductivity by addition of carbon and multiwall carbon nanotube (MWCNT) as well as combination with copper (Cu) powder. Multiwall carbon nanotube used from 0.1 wt%, 0.5 wt% to 1 wt% while the addition of Cu powder into PP/C was various from 0.1 wt%, 0.2wt% to 0.5wt% respectively. This research focuses on material design of composite based on polymer and carbon to improve an electrical conductivity according to electrical conductivity requirement for bipolar plate. Bipolar plate is one of the components in PEMFC constituted a crucial component that collects and transfers electron from the anode to the cathode, therefore it should possess high electrical conductivity. The main discussion in this research is to analyze the role of multiwall carbon nano tube (MWCNT) and copper on electrical conductivity of polymer composites produced. Functional groups analysis using Fourier Transform Infrared Spectroscopy (FTIR) was also carried out to investigate whether carbon has been mixed perfectly within polypropylene. It is found that the effect of adding a small amount of MWCNT and Cu have improved their electrical conductivity of composites up to 15.62 S/cm.

Kinetic Modeling of Carbon Nanotube Production and Minimization of Amorphous Carbon Overlayer Deposition in Floating Catalyst Method

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Leila Samandari-Masouleh ◽  
Navid Mostoufi ◽  
AA Khodadadi ◽  
Y. Mortazavi ◽  
Morteza Maghrebi
Keyword(s):  
Carbon Nanotubes ◽  
Amorphous Carbon ◽  
Kinetic Modeling ◽  
Carbon Deposition ◽  
Multiwall Carbon Nanotubes ◽  
Weight Ratio ◽  
Carbon Formation ◽  
Reactor Kinetic ◽  
Bottom To Top ◽  
Multiwall Carbon

Abstract A kinetic modeling of longitudinal and depth profiles of multiwall carbon nanotubes (MWCNTs) synthesis using xylene and ferrocene in a floating catalyst (FC) reactor is hereby reported. Both amorphous and arrays of carbon nanotubes (CNTs) are formed, whose ratio sharply increases along a growth window and from the bottom to top of the arrays. A model is presented for the rate of CNTs synthesis as well as the rate of amorphous carbon formation which undesirably forms on the nanotube walls and reduces nanotubes quality and synthesis efficiency. Based on the amounts of amorphous carbons and CNTs formed in the reactor, kinetic parameters of formation of these species from xylene were estimated. It is shown that, as the temperature increases, the weight ratio of amorphous carbon to CNTs shows minimum at 970 K. The ratio increases with decreasing the amount of deposited iron. Increasing pressure and carrier gas is found to have marginal effects on producing CNTs with lower amounts of amorphous carbon. Higher surface density of CNTs (number of CNTs per surface area) and their diameter, result in a significantly higher amount of amorphous carbon deposition.

Carbon Nanotube Yarns as High Load Actuators and Sensors

2008 ◽  
Vol 61 ◽  
pp. 65-74 ◽  
Author(s):  
Tissaphern Mirfakhrai ◽  
Ji Young Oh ◽  
Mikhail Kozlov ◽  
Shao Li Fang ◽  
Mei Zhang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Quantum Chemical ◽  
Multiwall Carbon Nanotubes ◽  
High Load ◽  
Contributing Factors ◽  
The Past ◽  
Chemical Effects ◽  
Applied Tension ◽  
Multiwall Carbon

Carbon nanotubes have attracted extensive attention in the past few years because of their appealing mechanical and electronic properties. Yarns made through spinning multiwall carbon nanotubes (MWNTs) have been reported. Here we study the application of these yarns as electrochemical actuators, and as force sensors. MWNT yarns are mechanically strong with tensile strengths reaching one GPa. When charge is stored in the yarns they change in length. This is thought to be because of a combination of electrostatic and quantum chemical effects. We report strains up to 0.6 %. The charged yarns can also generate current and change in voltage in response to a change in the applied tension. Electrostatic and quantum effects contributing to actuation are introduced along with the effect of the yarn geometry on actuation and other contributing factors.

Thermal conductivity and flammability of multiwall carbon nanotube/polyurethane foam composites

2016 ◽  
Vol 53 (2) ◽  
pp. 215-230 ◽  
Author(s):  
JJ Espadas-Escalante ◽  
F Avilés ◽  
PI Gonzalez-Chi ◽  
AI Oliva
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Polyurethane Foam ◽  
Fire Behavior ◽  
Multiwall Carbon Nanotubes ◽  
Propagation Speed ◽  
Interfacial Thermal Resistance ◽  
Multiwall Carbon Nanotube ◽  
Multiwall Carbon

The thermal conductivity and fire response of multiwall carbon nanotube/polyurethane foam composites are investigated for ∼45 kg/m3 foams with multiwall carbon nanotube concentrations of 0.1, 1, and 2 wt.%. The thermal conductivity of such nanocomposites shows a modest increase with increased multiwall carbon nanotube content, which is explained by a high value of interfacial thermal resistance, as predicted by existent thermal models. A strong correlation between multiwall carbon nanotube content, foam’s cellular morphology, and fire behavior was observed. The flame propagation speed increases with the addition of 0.1 wt.% multiwall carbon nanotubes and then reduces as the multiwall carbon nanotube content increases. The mass lost after flame extinction reduces with the addition of multiwall carbon nanotubes, suggesting an increased resistance to flame attack due the multiwall carbon nanotube presence.

Enhancement of Dispersion Stability of Carbon Nanotube in Solvents

2013 ◽  
Vol 740 ◽  
pp. 449-454
Author(s):  
Ping Li ◽  
Low Aik Seng ◽  
Jin Lin ◽  
Yin Xi Jiang ◽  
Ong Guat Choon
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Multiwall Carbon Nanotubes ◽  
Dispersion Stability ◽  
Instability Index ◽  
Challenging Issue ◽  
Accelerated Stability ◽  
Anchoring Groups ◽  
Multiwall Carbon

Dispersion stability of carbon nanotubes (CNTs) is a challenging issue in the preparation of nanocomposites. This paper reports the enhancement of dispersion stability of multiwall carbon nanotubes (MWCNTs) in four solvents using two surfactants and four polymeric dispersants. The dispersion stability of MWCNTs, in term of Instability Index, was characterized by an accelerated stability analyser. The two polymeric dispersants with ionic anchoring groups and solvent-compatible chains showed the best dispersion stability as they provide polar anchoring and steric barrier which enhance the dispersion stabilisation of MWCNTs in various solvents.

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