Opportunities and Barrier Issues in Carbon Nanocomposites R. Byron Pipes, NAE, IVA Goodyear Endowed...
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Opportunities and Barrier Issues in Carbon Nanocomposites
R. Byron Pipes, NAE, IVA
Goodyear Endowed Professor
University of Akron
National Science Foundation Composites Workshop
June 9-10, 2004
The Future for Carbon Nanocomposites
• Future Trends in Technology Development• Globalization of Research• Barriers and Opportunities:
Scale
Mixing and Dispersion
Multi-Functionality
Next Generation Aerospace Material
Carbon Nanotube
Nanotube/ Polymer
Nanotube Fiber
Ultra Nanostructured Composite
Connect,ClickAnd
Control
Factory Production
Education
Chemical Plant
Heavy Machinery
DSC
TGAPolymer Industry
Process Control
Higher Level Research
Online Microscopy
Textile
The Future: Connect, Click and Control
Carbon Nanotubes
• Graphene is the stiffest material known (Young’s modulus > 1 TPa)
• Ideal reinforcement for composite materials
Single wall carbon nanotubesForms of Carbon
Diamond Buckyball
Graphite Nanotube100 nm
SCALE
Is it possible to span 12 orders of magnitude in scale and preserve
properties?
Self Similar Helical Modeling
SWCN
LatticeDymanics
Nano-wire
Micro-Mechanics
+Self Similar
Analysis
Polymer
Micro-fiber
Micro-Mechanics
+Self Similar
Analysis
Polymer
Lamina
Micro-Mechanics
+Self Similar
Analysis
Polymer
Nano-array
Self SimilarAnalysis
Self-Similar Scales
1.48 x 10-8 m
.
1.68 x 10-7 m
1.92 x 10-6 m
1.38 x 10-9 m
SWCN
SWCN Nano Array
SWCN Nano Wire
SWCN Micro Fiber
Self-Similar Scales
1.9 x 108
1.7 x 1010
1.6 x 1012
Diameter = 1.92 x 10-6 mLength = 1.0 x 10–3 m
Number of nanotubes
SWCN
Self-Similar Properties
0
200
400
600
800
1.E-10 1.E-09 1.E-08 1.E-07 1.E-06 1.E-05 1.E-04Diameter (m)
Sp
ec
ific
Mo
du
lus
(G
Pa
)
CarbonFiber
SWCN
Nano-wire
Nano-array
Micro-fiber
=10°
=20°
Lamina
Observations
• Nanotube – Nano Array – Nano Wire – Micro Fiber• Helical array geometry provides self-similar
platform • 71% stiffness reduction• Strength reduction may not correspond to stiffness
reduction• Multifunctional properties offer significant potential• Use the properties at the scale of applicability
Mixing and Dispersion
Van der Waals bonding – Energy for dispersion
Science 273, 483 (1996).
SWCN Array Image Analysis
DoDi
S
Do = 1.38 nm
Di = 0.73 nm
S = 1.48 nm
Nanotube Wall Thickness = 0.33 nm
Volume Fraction:Hexagonal Array = 0.79With van der Waals = 0.906
Shear and Bulk Moduli
x
2
x
3
o22321
o33
o32321
o22
xxx
xxx
o3xo3
o2o22
xxx
xxx
x
2
x
3
223
2
23 eVol4
1K
223
2
23 Vol
1G
Carbon Nanotubes Sticking Together
Continuum Approach for L-J Interactions
r
d
areaunit per atoms3
4
atoms 2for potential J-L4
),()(
2
22
612
2
0 0
b
drR
RRR
rdrddrRd
sheet
1 atom
Dilatation of SWCNT Array
4
3CellUnitofArea
2R
20
3
6
R
Cohesive Energy per unit Volume
Dilatational Cohesive Energy per Unit Volume
20
00
3
3
R
1
1.5
2
1 10 100 1000 10000
Number of Tubes
0Eactual
Unit Cell Cohesive Energy
Chirality R0, nm 0, nJ/m GJ/m3
(6,6) 1.1281 0.117 0.159
(10,10) 1.6723 0.152 0.207
(24,24) 3.5733 0.239 0.325
Conclusions for Array Flexural Properties
• The assumption that the CNT array can be represented as a uniform beam is not appropriate for arrays that are not fully bonded.
• The experimental results of Salvetat [3] for the 7- element array (4.5 nm diameter rope) with span lengths of 285 and 180 nm, revealed shearing tractions of 136 and 200 MPa, respectively.
• Fracture energies for SWCN fracture are significant!
Functionality
Can multifunctionality provide the pathway for accelerated adoption?
Are devices the fertile area?
Radial breathing mode spectra
Inte
ns
ity(
a.u
)Raman spectroscopyRaman spectroscopy
Higher Intensity in parallel polarization direction.
Similar result seen for both two grades of CNT
Orientation
0.5% nanotube(CS) composite microfiber
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
120 130 140 150 160 170 180 190 200 210 220
Perpendicular
Parallel
Raman shift(cm-1)
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
50000
1500 1525 1550 1575 1600 1625 1650 1675 1700
Perpendicular
Parallel
Tangential mode spectra