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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. What are CNT Composites?. “Distinct” molecules forming a single component Motivation for using composites
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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
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
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(3&4), pp 479, 2003
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
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
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
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
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
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)
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