scholarly journals Comparative Characterization of Multiscale Carbon Fiber Composite with Long and Short MWCNTs at Higher Weight Fractions

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Michael Zimmer ◽  
Qunfeng Cheng ◽  
Shu Li ◽  
James Brooks ◽  
Richard Liang ◽  
...  

There are documented advantages to using carbon nanotubes (CNTs) in composites for various property enhancements. However, to date, only limited studies have been conducted on using of longer CNTs over 1 mm in length. This study used long multiwalled carbon nanotubes (LMWCNTs) and their longer extended networks to test multiple properties in thermal conductivity, electrical conductivity, mechanical strength, and modulus and then compared these properties to those of shorter multi-walled carbon nanotubes (SMWCNTs). For carbon fiber-reinforced composites, the longer graphite paths from LMWCNTs in the matrix were expected to improve all properties. The longer networks were expected to allow for more undisturbed phonon transportation to improve thermal conductivity. This in turn relates to improved electrical conductivity and better mechanical properties. However, results have shown that the LMWCNTs do not improve or decrease thermal conductivity, whereas the shorter MWCNTs provide mixed results. LMWCNTs did show improvements in electrical, mechanical, and physical properties, but compared to shorter MWCNTs, the results in other certain properties varied. This perplexing outcome resides in the functioning of the networks made by both the LMWCNTs and shorter MWCNTs.

2005 ◽  
Vol 128 (2) ◽  
pp. 465-473 ◽  
Author(s):  
J. Samuel ◽  
R. E. DeVor ◽  
S. G. Kapoor ◽  
K. J. Hsia

The machinability of a polycarbonate nanocomposite containing multiwalled carbon nanotubes is investigated and contrasted with its base polymer and with a conventional carbon fiber composite. The material microstructures are characterized using transmission electron and scanning electron microscopy methods. Micro-endmilling experiments are conducted on the three materials. Chip morphology, machined surface characteristics, and the nature of the cutting forces are employed as machinability measures for comparative purposes. Polycarbonate chips are seen to transition from being discontinuous to continuous as the feed-per-tooth (FPT) increases, while, at all FPT values the nanocomposite is seen to form comparatively thicker continuous chips. The nanocomposite and the carbon fiber composite are seen to have the lowest and the highest magnitudes, respectively, for both the surface roughness and cutting forces. Shearing along the nanotube-polymer interface and better thermal conductivity are speculated to be the mechanisms responsible for the observations seen in the nanocomposite.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Pin-Ning Wang ◽  
Tsung-Han Hsieh ◽  
Chin-Lung Chiang ◽  
Ming-Yuan Shen

Graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) are novel nanofillers possessing attractive characteristics, including robust compatibility with most polymers, high absolute strength, and cost effectiveness. In this study, an outstanding synergetic effect on the grapheme nanoplatelets (GNPs) and multiwalled carbon nanotubes (CNTs) hybrids were used to reinforce epoxy composite and epoxy/carbon fiber composite laminates to enhance their mechanical properties. The mechanical properties of CNTs/GNPs hybrids on a fixed weight fraction (1 wt%) with mixing different ratio reinforced epoxy nanocomposite, such as ultimate tensile strength and flexure properties, were investigated. The mechanical properties of epoxy/carbon fiber composite laminates containing different proportions of CNTs/GNPs hybrids (0.5, 1.0, 1.5 wt%) were increased over that of neat laminates. Consequently, significant improvement in the mechanical properties was attained for these epoxy resin composites and carbon fiber-reinforced epoxy composite laminates.


Carbon ◽  
2008 ◽  
Vol 46 (15) ◽  
pp. 2026-2033 ◽  
Author(s):  
K.L. Kepple ◽  
G.P. Sanborn ◽  
P.A. Lacasse ◽  
K.M. Gruenberg ◽  
W.J. Ready

Author(s):  
Johnson Samuel ◽  
Richard E. DeVor ◽  
Shiv G. Kapoor ◽  
K. Jimmy Hsia

The machinability of a polycarbonate nanocomposite containing multiwalled carbon nanotubes is investigated and contrasted with its base polymer and with a conventional carbon fiber composite. The material microstructures are characterized using transmission electron and scanning electron microscopy methods. Micro end milling experiments are conducted on the three materials. Chip morphology, machined surface characteristics and the nature of the cutting forces are employed as machinability measures for comparative purposes. Polycarbonate chips are seen to transition from being discontinuous to continuous as the feed-per-tooth (FPT) increases, while, at all FPT values the nanocomposite is seen to form comparatively thicker continuous chips. The nanocomposite and the carbon fiber composite are seen to have the lowest and the highest magnitudes, respectively, for both the surface roughness and cutting forces. Shearing along the nanotube-polymer interface and better thermal conductivity are speculated to be the mechanisms responsible for the observations seen in the nanocomposite.


2018 ◽  
Vol 83 (2) ◽  
pp. 20901 ◽  
Author(s):  
Ahmed Chaouki Lahrech ◽  
Bachir Abdelhadi ◽  
Mouloud Feliachi ◽  
Abdelhalim Zaoui ◽  
Mohammed Naїdjate

This paper proposes a contactless method for the identification of the electrical conductivity tensor of a carbon fiber composite materials plate using a rotating magnetic field and multi-coil eddy current sensor. This sensor consists of identical rectangular multi-coil, excited by two-phase sinusoidal current source in order to generate a rotating magnetic field and to avoid the mechanical rotation of the sensor. The fibers orientations, the longitudinal and transverse conductivities in each ply of carbon fiber composite material plate were directly determined with analysis of the impedance variation of each coil as function of its angular position. The inversion process is based on the use of artificial neural networks. The direct calculation associated with artificial neural networks makes use of 3D time-harmonic finite element method based on the A, V–A formulation.


2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
C. Kostagiannakopoulou ◽  
E. Fiamegkou ◽  
G. Sotiriadis ◽  
V. Kostopoulos

The present study attempts to investigate the influence of multiwalled carbon nanotubes (MWCNTs) and graphite nanoplatelets (GNPs) on thermal conductivity (TC) of nanoreinforced polymers and nanomodified carbon fiber epoxy composites (CFRPs). Loading levels from 1 to 3% wt. of MWCNTs and from 1 to 15% wt. of GNPs were used. The results indicate that TC of nanofilled epoxy composites increased with the increase of GNP content. Quantitatively, 176% and 48% increase of TC were achieved in nanoreinforced polymers and nanomodified CFRPs, respectively, with the addition of 15% wt. GNPs into the epoxy matrix. Finally, micromechanical models were applied in order to predict analytically the TC of polymers and CFRPs. Lewis-Nielsen model with optimized parameters provides results very close to the experimental ones in the case of polymers. As far as the composites are concerned, the Hashin and Clayton models proved to be sufficiently accurate for the prediction at lower filler contents.


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