thermodynamics and kinetics of engineered carbon nanotubes composite polymers
Download
Skip this Video
Download Presentation
Thermodynamics and Kinetics of Engineered Carbon Nanotubes Composite Polymers

Loading in 2 Seconds...

play fullscreen
1 / 26

Thermodynamics and Kinetics of Engineered Carbon Nanotubes Composite Polymers - PowerPoint PPT Presentation


  • 179 Views
  • Uploaded on

Thermodynamics and Kinetics of Engineered Carbon Nanotubes Composite Polymers. Lior Zonder. THE 5 th INTERNATIONAL CONFERENCE Nanotechnology Applications for the Plastics & Rubber Industries Monday February 1 st , 2010. Motivation. Carbon nanotubes (CNT) Mechanical properties

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Thermodynamics and Kinetics of Engineered Carbon Nanotubes Composite Polymers' - betty_james


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
thermodynamics and kinetics of engineered carbon nanotubes composite polymers

Thermodynamics and Kinetics of Engineered Carbon Nanotubes Composite Polymers

Lior Zonder

THE 5th INTERNATIONAL CONFERENCE

Nanotechnology Applications

for the Plastics & Rubber Industries

Monday February 1st, 2010

motivation
Motivation
  • Carbon nanotubes (CNT)
    • Mechanical properties
    • Electrical properties
  • Enhancement of electrical properties of high performance polymer compounds
    • Electrostatic dissipation
    • Electrostatic painting
    • EMI shielding
    • Transparent electrical conductors
    • Lightweight conductive materials
      • PEM fuel cells

Marx, G.K.L., et al., Applied Physics Letters, 2003. 83(14): p. 2928.

motivation3
Motivation
  • Conductive plastics
    • Not new concept
    • Formation of 3D network throughout the bulk

10%

1%

  • Carbon nanotubes
  • Low percolation threshold
  • Due to aspect ratio
  • Carbon black
  • High loadings
  • Loss of mechanical properties
motivation4
Motivation
  • Further reduction in filler content achieved by matrix morphology control
    • Specific location of filler in multi-phase system
    • Percolation network forms in one phase or at the interphase
  • Double percolation concept

10-7

10-12-10-10

Wu, D., et al.,. Biomacromolecules, 2009. 10(2): p. 417-424.

objective
Objective
  • Understand the forces involved in determining CNT location in a two phase polymer blend
    • Thermodynamic
    • Kinetic
  • Establishing the relationship between mixing procedure, material morphology and properties
  • Develop a model relating kinetic and thermodynamic factors to final morphology
background
Background
  • Why CNT distribute unevenly in polymer blend?
    • thermodynamics: particles interact more favorably with one of the polymers thus decreasing the system’s free energy
    • kinetics: viscosity ratio as a distributing factor
  • What are the circumstances that cause one factor to dominate over the other?
thermodynamics
Thermodynamics
  • Expressed in terms of interfacial interactions
  • Particle will tend to locate to minimize interfacial tension
  • Quantified by the wetting parameter

1

2

particles are present only in polymer 1

Particles are present in polymer 2

particles are concentrated at the interface between the polymers

thermodynamics8
Thermodynamics

Issues

  • Interfacial energies between each polymer and filler are calculated using theoretical models
  • Temperature dependence of the surface energy
  • Melt mixing
    • Viscous polymer restrict rearrangement due to thermodynamic drive
    • Thermodynamic equilibrium is not obtained
kinetics
Kinetics
  • Melt mixing is a dynamic process
  • Final blend morphology and CNT dispersion state influenced by
    • Mixing procedure
      • Sequence of addition of components
      • Melting point difference

Elias L, Fenouillot F, Majeste´ J-C, Cassagnau P. Polymer 2007;48:6029–40.

+

kinetics cont
Kinetics- cont
  • Viscosity
  • Viscosity ratio as a distributing factor

Hydrophilic silica- prediction: particles in EVA

PP/EVA

All components added together

Hydrophobic silica- prediction: particles at the interface

Elias, L., et al., J. Polym. Sci B: 46(18): p. 1976-1983.

kinetics11
kinetics
  • Particle migration
    • Self diffusion
    • Shear induced

Time scale of motion for diffusing particles

Assume particle aggregate size

Temp

Viscosity of polymer

slide12

Shear significantly accelerates particle migration

    • Only when thermodynamic drive exists

+

<

<

Hong, J.S., et al.,. J. Appl. Polym. Sci., 2008. 108(1): p. 565-575.

summary
Summary
  • At equilibrium particles locate to minimize free energy
  • Morphology and dispersion can be kinetically controlled
    • Slow down or accelerate migration of particles
      • Only if thermodynamic drive exists
  • When no thermodynamic drive exists, kinetics (viscosity ratio) is a dominate factor
experimental
Experimental

Material selection

  • PET- high performance engineering thermoplastic
  • Forms a non miscible, partially compatible blend with PVDF
  • The polymers have different polarities
methodology
Methodology
  • Melt blending of PET with 5,10,15%w PVDF with and without 0.5%w CNT in a batch mixer
  • PET neat, PVDF neat and PET+cnt, PVDF+cnt as control
  • All components added together
  • Tests
    • Parallel plate rheometer
    • Differential scanning calorimeter
    • Dynamic mechanical analysis
    • Scanning electron microscopy
rheology
Rheology
  • Polymer melt oscillated between parallel plate
  • Rheological and viscoelastic behavior of melts

PVDF, PVDF+CNT

3

PET+CNT,

PET/PVDF Blends+CNT

2

PET, PET/PVDF Blends

1

rheology18
Rheology
  • Appearance of shoulder with increasing amount of PVDF
  • CNT cancels the effect of the addition of PVDF

2

1

thermal analysis
Thermal analysis

PET,

PET+CNT

PVDF,

PVDF+CNT

thermal analysis20
Thermal analysis

95/5

90/10

85/15

preliminary conclusion
Preliminary conclusion
  • CNT located mostly in PET phase
  • Selective location of nanoparticles can be studied by tools such as rheometry and DSC
  • The presented work is a preliminary stage for a wider study
future work
Future work
  • Investigation of kinetic effects by
    • Sequential blending
    • Processing conditions
    • Altering viscosities by MW control
  • Relating rheological behavior to microstructure
  • Electrical properties characterization
ad