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? Nanotube in Polypropylene Sandler et al, J MacroMol Science B, B42(3&4), pp 479, 2003 Matrix and Reinforcement Connective forces van der Waals forces Covalent bonding Shared Properties Mechanical Load Thermal, Electrical conduction

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, (11): p

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 Improvement Methods

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

Unaligned Aligned Improvements to a polypropylene matrix due to various percentages of added carbon nanotubes Measured effects M.J. Biercuk, M.C. Llaguno, M. Radosavljevic, J.K. Hyun, A.T. Johnson Applied Physics Letters 80 (2002) p. 2767

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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