HKN - Meeting 4

1
Carbon Nanotube Composites Presentation by Jason
Morejon

• What are CNT Composites?
• How do they work?
• What affects how well they work?
• Improvement Methods
• Measured Effects

2
What are CNT Composites?

• Distinct molecules forming a single component
• Motivation for using composites
• Size
• Price of CNTs
• Large scale production
• Current uses for CNT Composites

3
How do they work?

• Matrix and Reinforcement
• Connective forces
• van der Waals forces
• Covalent bonding
• Shared Properties
• Mechanical Load
• Thermal, Electrical conduction

Nanotube in Polypropylene Sandler et al, J
MacroMol Science B, B42(34), pp 479, 2003
4
What affects how they work?

• Matrix substance
• Concentration
• Dispersion
• Orientation
• Anisotropic material
• Type of nanotube
• SWNT and MWNT
• Surface area vs volume
• Defects in nanotubes
• Metallic and Semiconductive

M.J. Biercuk, M.C. Llaguno, M. Radosavljevic,
J.K. Hyun, A.T. Johnson Applied Physics Letters
80 (2002) p. 2767
5
Improvement Methods

• Polycarbonate wrapping of MWNT
• Plasma deposition of 2-7nm polystyrene
• Improved dispersion
• Increased tensile strength and modulus
• Clearly defined interfacial adhesion layer

Ding W., et al, Direct observation of polymer
sheathing in carbon nanotube polycarbonate
composites. Nano Letters, 2003. 3(11) p.
1593-1597
6
Improvement Methods

• Dispersion
• Overcoming van der Waals interactions
• Easier with MWNT (less aggregation due to size)?
• Alignment
• Shown to improve mechanical properties and
  electrical and thermal conductivity
• Ultrasonic dispersion, Melt processing,
  electrospinning, electric fields, mechanical
  shear

7
Alignment - electrospinning

• Forced out by pump
• Held together by viscosity (or breaks into
  droplets)?
• Kept thin by electrostatic repulsion
• Produces nanometer-scale diameters of uniform
  fibers

http//en.wikipedia.org/wiki/Electrospinning
8
Measured effects
Unaligned Aligned
M.J. Biercuk, M.C. Llaguno, M. Radosavljevic,
J.K. Hyun, A.T. Johnson Applied Physics Letters
80 (2002) p. 2767
Improvements to a polypropylene matrix due to
various percentages of added carbon nanotubes
9
Measured Effects

• For 1 CNT a 5th-order decrease in resistivity
  achieved
• For Melt Blended CNT a 50 and 60 increase in
  modulus was achieved for 5 and 10 respectively
• A tensile strength of 1.8GPa has been reached
  (stronger than steel or spider silk)?

10
References

• 0 F. Hussain, M. Hojjati, M. Okamoto, R. Gorga,
  Journal of Composite Materials 40 (2006), p. 1511
• 1 R. Andrews, D. Jacques, A.M. Rao, T.
  Rantell, F. Derbyshire, Applied Physics Letters
  75 (1999), p. 1329.
• 2 M.J. Biercuk, M.C. Llaguno, M.
  Radosavljevic, J.K. Hyun, A.T. Johnson Applied
  Physics Letters 80 (2002) p. 2767.
• 3 A. Dalton, S. Collins, E. Munoz, J. Razal,
  V.H. Ebron, J. Ferraris, J. Coleman, B. Kim, R.
  Baughman, Nature 423 (2003), p. 703.
• 4 A.R. Bhattacharyya, T.V. Sreekumar, Tao Liu,
  S. Kumar, L.M. Ericson, R.H. Hauge, R.E. Smalley,
  Polymer 44 (2003), p. 2373.
• 5 S. Kumar, H. Doshi, M. Srinivasrao, J.O. Park
  and D.A. Schiraldi, Polymer 43 (2002), p. 1701.
• 6 S. Kumar, T.D. Dang, F.E. Arnold, A.R.
  Bhattacharyya, B.G. Min, X. Zhang, R.A. Vaia, C.
  Park, W.W. Adams, R.H. Hauge, R.E. Smalley, S.
  Ramesh and P.A. Willis. Macromolecules 35 (2002),
  p. 9039.
• 7 W. Feng, X.D. Bai, Y.Q. Liang, X.G. Wang, K.
  Hoshino. Carbon 41 (2003), p 1551