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1204-K18-48

Dynamic Mechanical Analysis of Bulk Carbon Nanotube Materials Brian T. Moses1, Paul R. Jarosz1, Chris M. Schauerman1, Jack Alvarenga1, Brian J. Landi1, Ryne P. Raffaelle1* 1

Nanopower Research Labs, Rochester Institute of Technology, Rochester, NY 14623, U.S.A.

ABSTRACT Several purification and processing techniques for laser-produced single wall carbon nanotube (SWCNT) soot were investigated and the resulting changes in the mechanical properties were characterized. SWCNT ribbons had non-nanotube carbonaceous content modified via thermal oxidation and the relationship between oxidation parameters and mechanical strength studied. SWCNT/polyamide composites were developed and exhibited improved toughness, tensile strength and elongation before break. The composite material is observed to have a greater tensile strength than either the baseline paper or the added polyamide. INTRODUCTION Purified SWCNT’s produced via laser ablation have been successfully applied in form factors similar to copper, such as flat ribbons and cylindrical wires[1,2]. The structural properties of these nanotube materials are dominated by the van der waals force between individual and bundled nanotubes[3]; In order to improve the strength of bulk SWCNT material, this force can be strengthened through densification and alignment of the nanotube bundles. Alternatively, the forces between nanotubes can be augmented by filling void spaces with compounds capable of efficiently transferring stress to the nanotubes[4,5]. Morphological changes to the material through purification via thermal oxidation [6, 7] and inclusion of impurities, dopants, and other compounds have a distinct effect on the mechanical properties. In this work, the reduction in tensile strength of a nanotube ribbon is measured as a function of thermal oxidation time and temperature, removing non-nanotube carbonaceous material from said SWCNT ribbon. Additionally, Nylon 6-3 is added to a nanotube paper and the increase in tensile strength is measured. Optimized treatment to maximize the strength/weight ratio is discussed. EXPERIMENT Thermal Oxidation Effects on CNT Paper Tensile Strength Carbon nanotubes were produced using established laser-ablation techniques according to reported procedure with a pulsed Nd-YAG laser in a nitrogen atmosphere, followed by a 15 hour Nitric /HCl acid reflux to remove metal catalyst particles[8,9]. The resulting dispersion was filtered through and dried onto a 1 µm Teflon paper, resulting in a paper of ~ 30 µm thickness consisting of both nanostructured (NC) carbon and SWCNTs. Thermal oxidation is the standard method for removing the amorphous carbon from this material [7, 10]; In this work, the time and temperature of oxidation are varied, and the mechanical strength and elastic modulus of the material is measured. Characterization was performed using a TA Instruments Q800 Dynamic Mechanical Analyzer , which allows direct measurement of tensile strength and elastic modulus.

Nylon-SWCNT Paper Composite Materials Addition of a polyamide