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Dissertation
Carbon nanotube reinforced carbon nano composite fibrils by electro-spinning
Doctor of Philosophy (Ph.D.), Drexel University
2002
DOI:
https://doi.org/10.17918/etd-17
Abstract
Fibers of Polyacrylonitrile (PAN) are the precursor of 90% of produced carbon fibers. It is generally thought that the better the degree of molecular orientation in the original PAN fiber, the better the mechanical properties, in particular the modulus of the resultant fibers. Electro-spinning is a unique process in that it is able to produce polymer fibers having diameters ranging over seve ral orders of magnitude, from the micrometer range typical of conventional fibers down to the nanometer range. Until now and based on the literature review the shape and pattern of produced fibers in all electro-spun polymer solutions have taken an in-plan random pattern and affected by the shape of the collector, which gives a limitation of using these ultra fine produced fibers in textile applications. A notable phenomenon has been recognized under certain spinning conditions for PAN solution, which enable the production of continuous yarn containing partially oriented nano-fibers. This phenomenon opened the door to achieve many objectives such as the production of carbon-carbon nano composites by dispersing (CNT) of superior physical properties inside the PAN polymer solution and producing continues carbonnanotube reinforced PAN based carbon nano composite fibrils. The present study is an attempt to optimize the electro-spinning process for nanoscalefibers, understand the electro-mechanics of electro-spun continuous nano-fiber yarns, stabilize, carbonize and graphitize of nano fiber yarns with and without CNT and finally study the physical, chemical and mechanical properties of the produced carbon nanotube reinforced PAN based carbon nano composit e fibrils before and after heat treatments. The HREM results showed a good alignment for the CNT inside the PAN based carbon nano fiber composites as well as an increase in the crystallite size up to 5nm, which calculated based on Raman spectroscopy measurements. The AFM showed a two-folds increase in the composite modulus more than the calculated modulus from the rule of mixtures in stabilized case while it reduced to 1.3folds after graphitization. However, that increase defined as 'nano effect' has been explained as a result of the interaction between the nano reinforcements (CNT) and PAN polymer molecular chains.
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Details
- Title
- Carbon nanotube reinforced carbon nano composite fibrils by electro-spinning
- Creators
- Ashraf Abd El-Fattah Ali - DU
- Contributors
- Frank K. Ko (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Materials (Science and) Engineering (Metallurgical Engineering) [Historical]; College of Engineering (1970-2026); Drexel University
- Other Identifier
- 17; 991014632558604721