Aligned MWCNT-Reinforced Bulk Epoxy-Matrix Composites by Dielectrophoretic Force

2012 ◽  
Vol 538-541 ◽  
pp. 2224-2231 ◽  
Author(s):  
Ming Wen Wang ◽  
Niann I Yu ◽  
Wen Hao Liao
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Carbon Nanotube ◽  
Electric Field ◽  
Epoxy Matrix ◽  
Flexural Modulus ◽  
Weight Fraction ◽  
Low Carbon ◽  
Continuous Application

Studies have proved that enhancing epoxy matrices by adding carbon nanotubes to form structural reinforcements has significantly improved mechanical properties at very low carbon nanotube loading. That mechanical properties of aligned composites are better than those of random ones has been demonstrated in past studies; however, alignment is not easy to achieve in carbon nanotube epoxy-matrix bulk composite by conventional techniques. In this study, epoxy-matrix bulk composites reinforced by aligned multi-walled carbon nanotubes (MWCNTs) are prepared using an RF electric field to elicit dipolar interactions among the nanotubes in a viscous matrix following immobilization by curing under continuous application of an anisotropic electric field and the fracture toughness is experimentally characterized later. The processes of actively aligned MWCNTs epoxy-matrix bulk composite were controlled as a function of CNT weight fraction, the frequency of dielectrophoretic field and processing time. Carbon nanotubes are not only aligned along the field but also migrate laterally to enhance thickness. Eventually, addition of nanotubes improved the mechanical properties of the MWCNT/epoxy bulk composites, and the increase in the flexural modulus and fracture toughness with the aligned nanotube composite is two times greater than the improvement for the randomly oriented composite.

Alignment of MWCNTs in Polymer Composites by Dielectrophoresis

2008 ◽  
Author(s):  
Ming-Wen Wang
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotube ◽  
Electric Field ◽  
Polymer Composites ◽  
Flexural Modulus ◽  
Low Carbon ◽  
Multi Wall Carbon Nanotubes ◽  
Structural Reinforcement ◽  
Ac Electric Field

Successful structural reinforcement of polymer matrices by carbon nanotube has been shown where significant improvement of mechanical properties was achieved at very low carbon nanotube loading. Due to the mechanical properties of aligned composites is better than random has been demonstrated; the conception is not easy to perform in carbon nanotube polymer composites via conventional techniques. Here, we report a novel operation to actively align and network multi-wall carbon nanotubes (MWCNTs) in a polymer matrix. In this process, MWCNTs were aligned via AC electric field induced dipolar interactions among the nanotubes in a viscous matrix followed by immobilization by curing polymerization under continued application of the anisotropic electric field. In situ SEM verified the electrostatic stabilization of the MWCNTs in the dispersion and the orientation and agglomeration caused by the dielectrophoretic force. Alignment of MWCNTs was controlled as a function of magnitude, frequency, and application time of the applied dielectrophoresis. In the present work, MWCNTs are not only aligned along the field, but also migrate laterally to form thick. The actively aligned MWCNTs amplify the flexural modulus and wear-resisting property.

Rheological and mechanical properties of tape-casted zirconia-toughened alumina composite thick films reinforced with multiwalled carbon nanotubes

2019 ◽  
Vol 54 (17) ◽  
pp. 2353-2363
Author(s):  
SH Mussavi Rizi ◽  
M Ghatee
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Carbon Nanotube ◽  
Phase Distribution ◽  
Thick Films ◽  
Tape Casting ◽  
Composite Films ◽  
Multiwalled Carbon ◽  
Zirconia Toughened Alumina

This paper reports the effects of adding carbon nanotubes on the mechanical properties of zirconia-toughened alumina thick films prepared by tape casting. Polyvinylpyrrolidone, polyvinyl alcohol, and glycerin were used as dispersant, binder, and plasticizer, respectively. The microstructure and phase content of the samples were studied using scanning electron microscopy and X-ray diffraction methods, respectively. Mechanical properties of thick composite films were investigated by microhardness and nanoindentation methods. It was determined that polyvinylpyrrolidone can be used as a dispersant for carbon nanotube, alumina, and zirconia particles; tape casting can produce thick films with homogeneous phase distribution, and that adding up to 0.01 wt.% carbon nanotube enhanced the zirconia-toughened alumina hardness by more than 30%, and fracture toughness about 40%. Increasing carbon nanotube content over 0.01 wt.% up to 0.1 wt.% increases microhardness and nanohardness but does not affect fracture toughness significantly.

Carbon Fibre-Organoclay Hybrid Epoxy Composites: Fracture Behaviours and Mechanical Properties

2006 ◽  
Vol 312 ◽  
pp. 179-186
Author(s):  
Jang Kyo Kim ◽  
Naveed A. Siddiqui ◽  
Ricky S.C. Woo ◽  
Christopher K.Y. Leung ◽  
Arshad Munir
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Epoxy Resin ◽  
Epoxy Matrix ◽  
Hybrid Composites ◽  
Flexural Modulus ◽  
Xrd Analysis ◽  
Interlaminar Fracture ◽  
The Matrix ◽  
Interlaminar Crack

The fracture resistance and mechanical properties of carbon fiber reinforced composites (CFRPs) containing organoclay-filled epoxy resin are studied. The XRD analysis and TEM examination revealed well-dispersed organoclay in the epoxy matrix displaying a mixture of exfoliation and intercalation. There was a significant improvement in flexural modulus and a marginal reduction in flexural strength of epoxy matrix due to the incorporation of organoclay. The quasi-static fracture toughness of epoxy increased nearly 60% with the addition of 3wt% clay, but there was a 45% drop in impact fracture toughness with 1wt% clay. When CFRPs were fabricated with the clay-modified epoxy resin, both the flexural modulus and strength of the hybrid composites showed negligible changes due to a few wt% of organoclay in the matrix. The interlaminar crack growth stability and the corresponding mode I interlaminar fracture toughness of the hybrid composites with organoclay improved substantially compared to those with carbon fibres only. The hybrid composites typically presented rough matrix surface associated with pinning and crack tip bifurcation, whereas the composite made from neat epoxy showed a smooth river line structure which is characteristic of brittle epoxy. The correlation between the composite interlaminar fracture properties and the toughness of modified matrix is discussed.

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.

scholarly journals Effects of CNT Addition on Mechanical Properties, Electric Conductivity and Oxidation Resistance of Al2O3-TiC Composite

2013 ◽  
Vol 761 ◽  
pp. 83-86
Author(s):  
Hideaki Sano ◽  
Junichi Morisaki ◽  
Guo Bin Zheng ◽  
Yasuo Uchiyama
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Electric Conductivity ◽  
Young’S Modulus ◽  
Oxidation Resistance ◽  
Young's Modulus ◽  
Tic Particle

Effects of carbon nanotubes (CNT) addition on mechanical properties, electric conductivity and oxidation resistance of CNT/Al2O3-TiC composite were investigated. It was found that flexural strength, Young’s modulus and fracture toughness of the composites were improved by addition of more than 2 vol%-CNT. In the composites with more than 3 vol%-CNT, the oxidation resistance of the composite was degraded. In comparison with Al2O3-26vol%TiC sample as TiC particle-percolated sample, the Al2O3-12vol%TiC-3vol%CNT sample, which is not TiC particle-percolated sample, shows almost the same mechanical properties and electric conductivity, and also shows thinner oxidized region after oxidation at 1200°C due to less TiC in the composite.

Fabrication of Carbon Nanotube Reinforced Boron Carbide Composite by Hot-Pressing Following Extrusion Molding

2014 ◽  
Vol 616 ◽  
pp. 27-31 ◽  
Author(s):  
Tomohiro Kobayashi ◽  
Katsumi Yoshida ◽  
Toyohiko Yano
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Carbon Nanotube ◽  
Boron Carbide ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Bending Strength ◽  
Extrusion Direction ◽  
Sem Observation

The CNT/B4C composite with Al2O3 additive was fabricated by hot-pressing following extrusion molding of a CNT/B4C paste, and mechanical properties of the obtained composite were investigated. Many CNTs in the composite aligned along the extrusion direction from SEM observation. 3-points bending strength of the composite was slightly lower than that of the monolithic B4C. Elastic modulus and Vickers hardness of the composite drastically decreased with CNT addition. Fracture toughness of the composite was higher than that of the monolithic B4C.

scholarly journals Effects of Irradiation by UV- Acceleration on Mechanical Properties of Polymer Blends (Polyester: Starch)

2018 ◽  
Vol 21 (1) ◽  
pp. 147 ◽  
Author(s):  
Sihama I. Salih ◽  
Qahtan A. Hamad ◽  
Safaa N. Abdul Jabbar ◽  
Najat H. Sabit
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Polymer Blends ◽  
Modulus Of Elasticity ◽  
Unsaturated Polyester ◽  
Flexural Modulus ◽  
Weight Ratio ◽  
Weight Fraction ◽  
Elongation Percentage

This work covers mixing of unsaturated polyester (un- polyester) with starch powders as polymer blends and study the effects of irradiation by UV-acceleration on mechanical properties of its. The unsaturated polyester was mixing by starch powders at particle size less than (45 µm) at selected weight fraction of (0, 0.5, 1, 1.5, 2, 2.5 and 3%). These properties involve ultimate tensile strength, modulus of elasticity, elongation percentage, flexural modulus, flexural strength, fracture toughness, impact strength and hardness. The results illustrate decrease in the ultimate tensile strength at and elongation percentage, while increasing modulus of elasticity, with increasing the weight ratio of starch powder to 3 % weight fraction, whereas the maximum value of hardness and flexural, impact properties happened at 1 % weight fraction for types of polymer blends.

Hydrogenated carbon nanotube-based spin caloritronics

2017 ◽  
Vol 19 (32) ◽  
pp. 21507-21513 ◽  
Author(s):  
Hong-Li Zeng ◽  
Yan-Dong Guo ◽  
Xiao-Hong Yan ◽  
Jie Zhou
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electric Field ◽  
Gate Voltage ◽  
Seebeck Effect ◽  
Partial Hydrogenation ◽  
Spin Caloritronics ◽  
Spin Seebeck Effect ◽  
Or Gate

The spin-Seebeck effect (SSE) in linearly hydrogenated carbon nanotubes (CNTs) is realized, where partial hydrogenation makes CNTs acquire magnetism. Moreover, an odd–even effect of the SSE is observed, and the even cases could be used as spin-Seebeck diodes, without the need for an electric field or gate voltage.

Electronic and Mechanical Properties of Super Carbon Nanotube Networks

2006 ◽  
Vol 963 ◽  
Author(s):  
Vitor R. Coluci ◽  
Socrates O. Dantas ◽  
Ado Jorio ◽  
Douglas s Galvao
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Tight Binding ◽  
Deformation Mechanisms ◽  
Different Types ◽  
Dynamics Simulations ◽  
Walled Carbon Nanotubes ◽  
Carbon Nanotube Networks ◽  
Main Deformation

ABSTRACTEletronic and mechanical properties of ordered carbon nanotube networks are studied using molecular dynamics simulations and tight-binding calculations. These networks are formed by single walled carbon nanotubes (SWNT) regularly connected by junctions. The use of different types of junctions (“Y”-, “X”-like junctions, for example) allows the construction of networks with different symmetries. These networks can be very flexible and the elastic deformation was associated with two main deformation mechanisms (bending and stretching ) of the constituents SWNTs. Rolling up the networks, “super” carbon nanotubes can be constructed. These super-tubes share some of the main electronic features of the SWNT which form them but important changes are predicted (e.g. reduction of bandgap value). Simulations of their deformations under tensile stress have revealed that the super-tubes are softer than the corresponding SWNT and that their rupture occur in higher strain values.

Preparation and Mechanical Properties of Epoxy Resin Reinforced with Jeffamines-Grafted Carbon Nanotubes

2009 ◽  
Vol 79-82 ◽  
pp. 553-556 ◽  
Author(s):  
Ling Fei Shi ◽  
Gang Li ◽  
Gang Sui ◽  
Xiao Ping Yang
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Epoxy Resin ◽  
Photoelectron Spectroscopy ◽  
Epoxy Matrix ◽  
Resin Matrix ◽  
Mechanical And Thermal Properties ◽  
Time Dynamic ◽  
Multi Walled Carbon Nanotubes ◽  
The Impact

The increasing proliferation and application of advanced polymer composites requires higher and broader performance resin matrices. Poly(oxypropylene) with –NH2 end-groups has been widely used to toughen epoxy resins, but the strength of resin matrix may be reduced due to the addition of flexible segments in the crosslinking network. Carbon nanotubes (CNTs) have been paid more and more attention in recent years because of their superior thermal and mechanical properties. In this paper, CNTs grafted with Jeffamines T403 were used to simultaneously improve the reinforcement and toughening of an epoxy resin. The untreated multi-walled carbon nanotubes (u-MWNTs) were functionalized with amine groups according to three steps: carboxylation, acylation, and amidation. The f-MWNTs were characterized by Fourier transform infra-red (FTIR) and X-ray photoelectron spectroscopy (XPS). The experimental results indicated that the T403 was grafted to the surface of MWCNTs. The mechanical and thermal properties of epoxy with f-MWNTs were investigated. The tensile and flexural strength increased by 7.77 % and 7.03 % after adding 0.5wt% f-MWCNTs without sacrificing the impact toughness. At the same time, dynamic mechanical thermal analysis (DMTA) showed that the glass transition temperature (Tg) of epoxy with f-MWNTs were increased. The fracture surface of epoxy with f-MWNTs was observed by scanning electron microscopy (SEM) to understand the dispersion of f-MWNTs in epoxy matrix and interfacial adhesion between f-MWNTs and epoxy matrix, which can be attributed to the strong interfacial bonding between f-MWNTs and epoxy resin.

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