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Synthesis of Carbon Nanofibers and Carbon Nanofiber-Carbon Nanotubes Using Poly Vinyl Alcohol Through Electrospinnig Approach

Azami Ghadikolaei, Milad | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44036 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Faghihi Sani, Mohammad Ali
  7. Abstract:
  8. The aim of the present thesis was a synthesis of carbon nanofibers (CNFs) derived from electrospun poly vinyl alcohol (PVA) by means of various stabilizers and, moreover, improvement of synthetic CNFs with the incorporation of carbon nanotubes (CNTs). In order to do so, PVA solutions were prepared and electrospun with and without the cadmium salt. In order to do so, PVA solutions were prepared and electrospun with and without the presence of cadmium salt. The resultant polymeric nanofibers were carbonized directly and indirectly. In the case of indirectly carbonization, they were iodinated before the carbonization process. In the case of CNF-CNT composites, after having oxidized by nitric acid, CNTs were scattered in PVA solution and subsequently were electrospun. Thermo gravimetric analysis (TGA), X-ray diffraction (XRD), Raman spectroscopy, and field emission scanning electron microscopy (FE-SEM) were employed to study the structural and morphological properties of samples. XRD analyses show that carbon yield increased 14, 8 and 14.8 times as a result of iodine, cadmium salt and both of them incorporation, respectively. SEM micrographs indicate that iodine and cadmium salt lead to increment and reduction of fiber diameters, respectively. In addition, Raman and XRD analyses donate the the improvement of crystallinity degree (13.5%), as well as crystallite size (32%), of CNFs including CNTs samples synthesized by iodine compare to cadmium sat. arropos of CNF-CNT composites, both crystallinity and crystallite size of CNFs, as well as growth rate of crystalline phase with temperature increment, were increased as a consequence of CNTs addition. Incorporation of CNTs in CNFs synthesized by iodine, cadmium salt and them both results in crystallite size growth of 32, 42, and 41%, respectively
  9. Keywords:
  10. Electrospinning ; Carbon Nanotubes ; Nanocomposite ; Poly Vinyl Alcohol ; Carbon Nanofiber

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