Engineering Carbon Nanotube Composites: Synthesis, Fabrication and Properties CIV4211: Final Year Project Samuel Chuah 21642303
Engineering
Carbon Nanotube Composites: Synthesis, Fabrication and Properties
CIV4211: Final Year Project
Samuel Chuah 21642303
2CIV4211: Final Year Project
Presentation outline
IntroductionAimStage 1: Literature Review Stage 2: ExperimentConclusion
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IntroductionCarbon Nanotubes (CNT) are:Nano-sized cylindrical tubes composed of sheets of carbon atoms
Discovered in 1991 by Sumio Ijima in his study of arc-discharge products
Schematic of a CNT
SEM image of CNT
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Introduction Usually produced by arc evaporation
Exceptional mechanical, thermal and electrical
properties
High aspect ratio
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Problem Statement:
Reason:1.CNT tend to agglomerate and entangle
2.Strong van der Waals attractive force
3.Weak CNT-matrix interaction
Solution: Dispersion
“CNT-epoxy composite has slightly better mechanical properties than pure epoxy”
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Aims Study the characteristics of CNT to realize its full potential
Understand the role of carbon nanotube geometry on
efficient dispersion
Harnessing the superior properties of nanocarbon in the
construction industry
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Learning mechanism
ExperimentLiterature Review
Simulation/ Modelling
Stage 1: Literature ReviewCNT Properties:Density: 1.4 to 2.1 g/cm3
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Properties CNT CNT Epoxy Composite
Young’s Modulus 1000 GPa 1 to 2.7 GPa
Tensile Strength 13 to 53 GPa 1 to 3 MPa
Flexural Strength 13 to 15 GPa 30 to 70 MPa
Stage 1: Literature ReviewComposite Characteristics
Reinforcement: High strength of the carbon fibre
Matrix: Epoxy protects CNT
Successful composite requires treatment
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Stage 1: Literature ReviewCNT Fabrication:Dispersion Methods:
Chemical: solvent type, surfactant, CNT functionalization
Physical: High speed shear mixing and ultrasonication
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Stage 2: Experiment
Aim: Investigate effect of CNT geometry
Method
1.CNT mixed with ethanol and surfactant
2.Sonication with a horn sonicator
3.UV-vis method and visual observation
4.Scanning electron microscopy (SEM)
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Stage 2: ExperimentAdsorption Spectrum
Peak at about 260nm
Strong absorption by dispersed CNT
Absorbance decreases: Scattering
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Figure 1: Normalized UV-vis adsorption spectrum of CNT in ethanol at continuous power of 25 W.
Stage 2: ExperimentCNT Diameter
Poor dispersion in small
diameter CNT
Smaller diameter = large surface
area.
More surfactant molecules
needed
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Figure 2: Effect of CNT diameter on CNT dispersion in ethanol solvent.
Stage 2: ExperimentCNT Length
CNT length insignificant
TSA:V is independent of length
Van Der Waals
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Figure 3: Effect of CNT length on CNT dispersion in ethanol solvent.
Conference Paper
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Conclusion
Dispersion is key to enhance mechanical properties
Experiment: Fabrication, CNT laboratory testing
CNT geometry
o Diameter
o Length
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THANK YOU
Questions?
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Glossary Aspect ratio: Ratio of length to diameter in a tube
Surfactant: Substance that promotes dispersion of CNT. In the experiment, dispersing agent was BYK9076, an Alkylammonium salt of a high molecular weight copolymer
Functionalisation: Chemically attach certain molecules (functional groups) to their smooth sidewalls without significantly changing the CNT desirable properties
Shear Mixing: Flow of the medium respond to an external force generates local shear stresses that causing dispersion
Uv-vis: correlates intensity of absorption of UV-visible radiation to the amount of substance present in a solution
SWNT: tubes of graphite that are normally capped at the ends with a single cylindrical wall
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Why Total Surface Area to Volume Ratio?
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SEM Image A: S1020, B: L1020, C: L2040, D: L4060
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Other ExperimentsExperiments were carried out to disperse the CNT
High Speed Shear Mixer Ultrasonication
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