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Study of Carbon Nanotube Sheets: Assembly, Texture Analysis and Applications

Gbordzoe, Seyram
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1527607439348766

Abstract Details

2017, PhD, University of Cincinnati, Engineering and Applied Science: Materials Science.
Carbon nanotubes (CNTs), simply described as a graphene sheet rolled into a tube, have been shown to have exceptional physical properties. However, transferring these properties from the nanoscale into a macroscale material made of CNTs has proven challenging. In order to advance practical applications, more attention is being paid towards exploring and processing CNTs into bulk materials such as sheets and in composites. This work examines the assembly and processing of CNT sheets and composites. Tailoring of such processed CNT materials requires them to be cut to micron accuracy dimensions. An increasingly popular method of achieving this is by laser cutting, and the effects of such a process on the structural and physical properties of CNT sheets are studied. Towards the goal of further improving the properties of CNT sheets, other post-processing methods are explored in this study. Better alignment and densification have been identified as some of the ways to enhance the properties of CNT sheets. It is demonstrated that depending on the solvent used for densification, the alignment achieved varies as the stretch ratio is increased. The physical properties of CNT sheets are shown to rely on the alignment and solvent used for densification. The orientation distribution function (ODF) obtained from X-ray pole figures is deployed as a novel technique to study the densification and alignment of CNT sheets. This technique is used to examine the effects of solvent densification and stretching on the alignment of CNT sheets. The best aligned CNT sheets densified with acetone and ethanol reveal an increase in tensile strength of 140% and 58% respectively over unaligned sheets. Some applications of CNT sheets based on resistive heating are reviewed in this work. The first application is the use of CNT sheets as heating materials. Here the design and fabrication of low voltage CNT heaters and their potential applications are reported. CNT sheets drawn from CNT arrays have been used to make the heaters. The sheet resistance of the CNT sheet is dependent on the number of layers accumulated during their formation and it ranges from 3.57 k?/sq. for a 1 layer sheet to 6.03 O/sq. for a 300 layer sheet. The fabricated and studied CNT heaters revealed fast heating and cooling rates. Potential applications of these heating devices have been illustrated by the manufacturing and testing of heated gloves and via deicing experiments using low voltage CNT heaters. CNT sheets are also explored for use in CNT-polymer composite fabrication. With the use of the resistive heating approach, CNT-polymer composites were manufactured that had improved mechanical properties over CNT sheets densified with only a solvent. CNT-polymer composites that were stretched showed an improvement in tensile strength, load and elastic modulus. Transmission electron microscopy (TEM) was employed to show the interaction between the polymers and CNTs. Thermoplastic polyurethane (TPU)-CNT and Ultem-CNT composites, which had good adhesion between CNTs and polymer, had an increase in tensile strength by as much as 86% and 77% respectively over pristine sheets.
Vesselin Shanov, Ph.D. (Committee Chair)
Gregory Beaucage, Ph.D. (Committee Member)
Jude Iroh, Ph.D. (Committee Member)
Mark Schulz, Ph.D. (Committee Member)
Sergey Yarmolenko, Ph.D. (Committee Member)
143 p.
Engineering

Recommended Citations

Citations

  • Gbordzoe, S. (2017). Study of Carbon Nanotube Sheets: Assembly, Texture Analysis and Applications [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1527607439348766

    APA Style (7th edition)

  • Gbordzoe, Seyram. Study of Carbon Nanotube Sheets: Assembly, Texture Analysis and Applications. 2017. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1527607439348766.

    MLA Style (8th edition)

  • Gbordzoe, Seyram. "Study of Carbon Nanotube Sheets: Assembly, Texture Analysis and Applications." Doctoral dissertation, University of Cincinnati, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1527607439348766

    Chicago Manual of Style (17th edition)

ucin1527607439348766
167
© 2017, some rights reserved.Creative Commons License Study of Carbon Nanotube Sheets: Assembly, Texture Analysis and Applications by Seyram Gbordzoe is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Cincinnati and OhioLINK.