Study on the Exfoliation of Graphite into Graphene by Electrochemical Method and Its Application in Thermoplastic Polyurethane Nanocomposite

Razeghi, Mohammad Ali | 2017

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 50230 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Pircheraghi, Gholamreza
  7. Abstract:
  8. Graphene is two dimensional nanomaterial, single layer of carbon atoms that exhibited excellent properties like high electrical conductivity and stiffness, but producing graphene and obtaining a good dispersion of graphene in a polymer matrix is still a major challenge. In this study by using the electrochemical route several graphene with different degree of oxidation produced in different electrolyte medium. According to XRD data, product of electrochemical exfoliation in dilute HNO3 medium includes 50% few-layer graphene (5 layers) and 25% GO and the rest are multi-layer graphene. Nonsolvent induced phase separation method were used to prepare TPU/Graphene nanocomposite. Different methods were used to characterize the microstructure and properties of samples including optical microscopy, rheological measurements, SEM, DSC and electrical conductivity. SEM images confirmed the porous microstructure of nanocomposite films. While, rheological and DSC measurements indicate that incorporation of GNPs changes the microstructure of segmented polyurethane by interaction between hard segments and nanofillers in the solution state and final sample, respectively. Finally, although graphene oxide is electrically insulated, it improves the dispersion of conductive graphene inside the TPU matrix, observed in SEM & optical microscopy images. This state of dispersion and formed 3D network of graphene/graphene oxide lead to 5 order of magnitude increase in conductivity of TPU porous nanocomposite films observed with only 3wt% of nanofiller
  9. Keywords:
  10. Thermoplastic Polyurethane ; Electrical Conductivity ; Graphene ; Nanocomposite ; Phases Separation ; Electrochemical Method

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