All ETDs from UAB

Advisory Committee Chair

Daneesh Simien

Advisory Committee Members

Selvum Pillay

William S Monroe

Document Type

Thesis

Date of Award

2015

Degree Name by School

Master of Science in Materials Engineering (MSMtE) School of Engineering

Abstract

Carbon nanotubes have been widely used as a reinforcement in polymer materials in various ways due to their high mechanical strength, excellent electrical conductivity, and great thermal conductivity. In this paper, we will investigate the effects of length and chirality of carbon nanotubes on the properties of nanocomposite as just mentioned. Therefore we demonstrate a carbon nanotubes length separation method, and further validate the length of individual fractional carbon nanotubes after separation by UV-Vis spectroscopy and atomic force microscopy (AFM). Chirality-separated, length-separated SWNT fraction via the ultracentrifugation technique is also demonstrated. Due to the differences in the scaling of buoyancy and frictional forces existing within carbon nanotubes, longer carbon nanotubes tend to travel with a greater velocity in opposition to applied acceleration. In this way, carbon nanotubes with different lengths will be pulled away from each other and eventually reach their equilibrium fraction under a consistent centrifugal force. This process will also allow researchers to conduct experiments to investigate the viscosity response of length sorted functionalized nanotubes in hydrocarbon-based structures. Further research includes the combination of the excellent electrical and thermal conductivity from carbon nanotubes into hydrocarbon based structures. The production and characterization of length sorted carbon nanotube fractions is the first step in assessing properties of the filler which will ultimately affect the viscosity of polymer fluids and melts. We will be able to uniquely define the particulate parameters of our systems and gain deeper understanding of the limitations of Einstein’s theorem of viscosity. This will have broader impacts in the development of materials processing standards of nanocomposite systems and the development of scalable processing methodology for producing homogeneous fractions of single length carbon nanotubes.

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