A comprehensive study on electrical and mechanical properties of CNT-polymer composites
Item
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Title
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A comprehensive study on electrical and mechanical properties of CNT-polymer composites
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Identifier
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d_2009_2013:d8a8750a8b6d:10212
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identifier
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10389
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Creator
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Ngabonziza, Yves,
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Contributor
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Jackie Li
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Date
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2009
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Language
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English
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Publisher
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City University of New York.
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Subject
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Mechanical engineering
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Abstract
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The aim of this dissertation is to study electrical and mechanical properties of carbon nanotube (CNT)-polymer composites. Two types of polymers, polypropylene (PP) and polycarbonate (PC) are chosen as polymer matrix materials. Synthesis, characterization and theoretical modeling of CNT composites are conducted.;In the processing of CNT composites, an injection molding method which is a melt mixing method is used to produce CNT-polymer composites. Processing parameters such as injection speed, temperature, pressure and time are optimized to obtain uniform samples. The influence of injection velocity on electrical and mechanical properties of the nanocomposites is studied in characterization.;In the experimental investigation of the produced nanocomposites, three types of testing are carried out: (i) the electrical conductivity of the samples is measured. The influence of CNT content and injection velocity on the electrical conductivity is then studied. (ii) Tensile tests under different strain rates are conducted. From this mechanical tensile testing, the elastic modulus and stress-strain relation can be obtained. Then these mechanical behaviors can be studied in terms of CNT content, injection velocity and strain rate loading. (iii) Electrical resistance measurement is carried out during the tensile tests for those with higher CNT contents than the percolation threshold. This allows us to study the piezoresistive behavior of CNT-polymer composites for sensing applications.;Finally, theoretical modelings are carried out to study electrical and elastic properties of CNT-polymer nanocomposites parallel to the experimental testing. First, a percolation theory is adopted to study the electric conductivity of the system in terms of CNT contents; the results are compared with our experimental data and the percolation threshold is determined. Second, a micromechanics theory with three different models is applied to study the elastic modulus of the nanocomposites. And last, a statistical approach is developed to investigate the resistance change under tensile loading. All results are compared with the experimental data.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Engineering
