الفهرس 
Theoretical Background and Literature SurveyOnly 14 pages are availabe for public view
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Abstract
Since graphene-based materials are finding increasingly more applications in various technological fields, it is of paramount importance to design these materials with useful and tunable properties by modification of the structural features of their building blocks.
The present work focuses on preparing and characterizing the pure Poly (vinyl chloride-co-vinylacetate-co-2-hydroxypropyl acrylate) (PVVH) copolymer and PVVH filled with various mass fractions of graphene oxide (GO) using different techniques. The new synthesized nanocomposite films have been prepared by solution casting technique.
To study physical properties of the prepared samples, different techniques had been used such as: X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy for studying structural properties, whereas scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) for investigating surface nature and thermal properties of the prepared samples, respectively. Electrical properties have been examined through measuring DC and AC electrical conductivities and dielectric constant.
XRD results demonstrated the presence of relatively sharp peak centered at 2 21.8, where its intensity decreased with increasing the filler content with increase in its broadness. This implies a decrease in the degree of crystallinity and causes an increase of amorphous regions consequently the conductivity.
The main characteristic peaks of the used materials were observed in FT-IR spectra with changes in their intensities and/or their positions, confirming the successful complexation and strong interaction between GO and PVVH.
The thermal behavior of the current samples was carefully investigated by employing TGA. The results obtained exhibited that the prepared nanocomposite with the highest content of GO (4 wt%) is stable up to 625 C and the thermal stability of the nanocomposites has been improved compared to that of pure PVVH, confirming the positive structural changes due to blending the current polymer with GO. This makes these samples are preferred in potential technological applications.
DC electrical conductivity study showed that the conductivity has been increased with increasing the filler content and this confirms results of XRD study. In AC electrical conductivity, it is observed that the AC conductivity of the sample of concentration 4 wt% depends upon both frequency and temperature, and enhanced with increasing both of them. This indicates the existence of charge carriers, which can be transported by hopping through defect sites along the PVVH matrix. A comparison between maximum barrier height and activation energy has been carried out to demonstrate the charge carriers transport mechanism.
In SEM technique, surface morphology has been considerably affected by incorporating GO into the PVVH matrix, and this change can be referred to as the physical interaction between them. It is noteworthy that no phase separation was detected in these micrographs, which provides a clear indication about the compatibility of the PVVH matrix with GO, confirming the successful complexation between them.
The PVVH-based nanocomposite with the highest concentration of GO (4 wt%) has achieved the highest enhancement in structural, morphological, thermal, electrical and mechanical properties, suggesting the feasibility of using it in designing electrochemical and energy storage devices.