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Engineering Carbon Nanotube Composites: Synthesis, Fabrication and Properties CIV4211: Final Year Project Samuel Chuah 21642303
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Feb 10, 2017

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Page 1: FYP presentation

Engineering

Carbon Nanotube Composites: Synthesis, Fabrication and Properties

CIV4211: Final Year Project

Samuel Chuah 21642303

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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

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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

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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.

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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.  

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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.

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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

21CIV4249: Foundation Engineering