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Title: Nano-reinforced epoxy resin composites with reduced graphene oxide
Author: Alzahrany, Ahmed
ISNI:       0000 0004 8501 4531
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2019
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Graphene has attracted intense scientific interest over the last decade because of its outstanding properties. However, to recover the properties of graphene, graphene oxide (GO) must be reduced. Several reduction approaches have been used to synthesis of reduced GO (RGO), but most of these approaches require the use of chemicals such as hydrazine that seem have a negative effect on the environment, and this was a significant consideration in the current study. The objective of my thesis is to development of simple, low-cost, environmental friendly and controllable approaches for the high (tube-furnace) and low (vacuum-oven-assisted) temperature reduction of GO to RGO and its effects on the processing and properties of incorporating nano-scale reinforcements in the matrix of epoxy (EP) to produce multi-scale composites. Moreover, this thesis investigated the dielectric properties of the RGO–SiO2/EP nanocomposites fabricated by the sol–gel process. The resulting RGO- based composites were characterised by a variety of different technique, including AFM, SEM, TEM, XPS, XRD, FTIR, Raman and TGA. The analysis revealed that these RGO-based composites have excellent properties and stability. We successfully applied the uniform dispersion of RGO sheets in Epoxy matrix to obtain Epoxy–RGO nanocomposites by embracing a combination of different dispersion techniques with presence of a tetrahydrofuran solvent, high shear mixing and bath sonication, for two different processing times of 90 and 30 min, respectively. The thermal conductivity of Epoxy was improved by up to 85%, reaching the maximum value of 0.36 W m-1 K-1 at 1.0 wt.% RGO as well as electrical conductivity improved by about seven orders of magnitude to 5.92×10-7 S m-1 . The resultant values indicated that the dielectric properties after a long time of dispersing presented a higher dielectric constant and dielectric loss than that of the RGO–SiO2/EP nanocomposites at a shorter time of dispersing. These results were fast and highly efficient compared with other report data.
Supervisor: Rehman, Ihtesham Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available