الفهرس 
Chapter 1 Introduction and Literature SurveyOnly 14 pages are availabe for public view
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Abstract
The present work focus on preparation, characterizing and studying the eco-friendly synthesized gold nanoparticles (AuNPs), and prepration of nanosized inorganic components with organic polymers results nanocomposites with good physical properties and chemical properties such as conductivity and optoelectronic properties. In addition, it is an economically available and versatile way to produce new materials and to overcome deficiency in some material characteristics. Polymer nanocomposite technologies have achieved an important position in the field of research and development of polymer science and in radiation processing of polymer. In addition, polymer composites show great promise in numerous applications. Part I: green synthesis of gold nanoparticles using Solanum nigrum, Ricinus communis, and Morus nigra leaves extracts: Eco-friendly synthesized gold nanoparticles (AuNPs) were successfully prepared via facile biosynthesis of plants leave extracts. Biosynthesized AuNPs were characterized by Ultraviolet/Visible spectroscopy (UV-vis.), Transmission electron microscopy (TEM), X-ray diffraction (XRD). UV/Vis. measurements of AuNPs prepared using Solanum nigrum shown broad absorption band in the visible region at 542 nm is assigned to the surface plasmon resonance (SPR) peak of AuNPs. But AuNPs prepared using Ricinus communis showed a broad absorption band at 525 nm is assigned to the SPR band of AuNPs, while AuNPs prepared using Morus nigra showed the broad absorption band centered at about 544 nm is assigned to the SPR peak of AuNPs. The typical TEM images of the obtained AuNPs have many shapes such as hexagonal, sphere and irregular shapes. XRD analysis was used to investigate the crystalline structure of the synthesized AuNPs. Part II: Preparation and characterization of polyethylene oxide/starch blend containing green synthesized gold nanoparticles: Casting technique was employed for preparation of polyethylene oxide (PEO)/ starch films (70/30 wt.%) with and without different concentrations of gold nanoparticles (AuNPs) as nanofiller which was biosynthesized by Ricinus communis leaf extract in the first system. In order to investigate the physical properties of the prepared samples, different techniques had been used such as X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy for structural properties, Ultraviolet and visible (UV/Vis.) spectroscopy for optical properties, Scanning electron microscopy (SEM) for surface morphology, Differential scanning calorimetry (DSC) for thermal properties DC electrical resistivity for electrical properties. XRD proved the semi-crystalline nature of the pristine and filled polymer blend and the degree of crystallinity in the prepared samples decreased as the AuNPs increased. FT-IR spectra depicted the main characteristic peaks of these materials and implied that complexation occurred in the amorphous region which confirms XRD results. UV/Vis. spectroscopy was used to retrace the optical changes with increasing Au content. Also, the UV/Vis. spectra exhibited a shift for the sharp absorption edge towards longer wavelength with increase the nanofiller content in the polymeric matrix. The red shift of the absorption edge in the filled PEO/starch indicates the complexation between the nanofiller and the polymer blend as in XRD and FT-IR analysis. SEM exhibited some granules appeared on surfaces of the filled samples as bright spots. These bright spots seem to be agglomerates of AuNPs. This confirms the interaction and complexation between the polymer blend and AuNPs. DSC thermographs confirmed the miscibility of blend components by showing a single Tg at around 69.37 oC. The resistivity-temperature plots show linear variation where it suggests an Arrhenius model and showed that Au NPs as promising candidate nanofiller for improving the electrical properties of the blend. DC electrical conductivity of the samples increased within the range 7.6210-11 to 2.0410-8 S.cm-1 at 353 K and electrical activation energy (𝐸𝑎) was decreased. Part III: Effect of gamma-irradiation on the structural, optical, thermal and electrical properties of PEO/starch blend doping various contents of gold nanoparticles: The XRD and FT-IR techniques have been used to investigate the structural properties for blend/Au nanocomposite before and after Gamma-irradiation at different doses (4, 6 and 8 Mrad). XRD measurements shown gradually decrease in intensity of crystalline peaks with increasing the gamma dose denotes a decrease in the amount of crystalline phase in the samples, indicating that the crystalline structure has been destroyed due to crosslinking. The FT-IR spectra shown the irradiated with different gamma-irradiation doses causes largely changes and effects on its functional groups in the polymeric matrix of PEO/starch blend with and without AuNPs. Also, gamma-irradiation doses cause appeared of the stretching vibrational bands of carbonyl group at 1723 cm-1 to be positively changed as the irradiation dose was increased. The value of electrical conductivity increased within the range 7.6210-11 of unirradiated pure samples to 2.0410-8 S.cm-1 of unirradiated samples doped with 0.40 % of AuNPs to 8.7010-8 S.cm-1 of irradiated (at 8 Mrad gamma-irradiation doses) samples doped with 0.40 % of AuNPs, at 353 K, which denotes the addition of AuNPs and gamma irradiation doses enhanced the electrical conductivity of blend. Part IV: Effect of gold nanoparticles on structural, optical, thermal and electrical Properties of Carboxymethyl Cellulose: Casting technique was employed for preparation of CMC with and without different concentrations of AuNPs as nanofiller which was biosynthesized by Ricinus communis leaf extract in the first system. The CMC was chosen because of its biocompatible, also Because of the scarcity of research in the field of nanocomposites of CMC/AuNPs. In order to, different techniques such as XRD, FT-IR spectroscopy, UV/Vis. Spectroscopy, SEM, DSC and DC electrical resistivity had been used to investigate the physical properties of the prepared samples. The XRD spectra of pure CMC exhibit hump centered at 2θ ≈ 21.5°, For the samples contain the AuNPs, it is clear that, there are decrease in the intensity without change in the position for the hump, This denotes a decrease in the degree of relative crystallinity. FT-IR spectra depicted The effect of AuNPs on the modes of vibrations was noticed in terms of decrease or increase in the intensity, broadening of the peaks with AuNPs concentration which result from the formation of cross-links between Au and ether oxygen atoms in CMC and coordination between Au. UV/Vis. Spectra shows that after addition AuNPs in CMC the SPR peak starts emerged with a red shift and the intensity continuously increases with increasing content of AuNPs. This red shift means that the particle size increases with increasing content of the nanofiller. SEM shown smooth and homogeneous surface without any aggregation for the pure sample. After addition Au nanoparticles to the pure CMC white granules and granules groups randomly distribution shows on the surface and did not show any aggregations except in the highest content, this confirms the interaction and compatibility between the AuNPs and the CMC. DSC curves showed decrease in the Tg value is with increasing the AuNPs concentration except in the highest concentration. The decrease in Tg means that a decrease in the degree of crystallinity and the segmental mobility of amorphous polymer increases because of the addition of AuNPs filler and become less rigid segments. The DC conductivity (σ) exhibited linear variation (no phase transition) of log σ with reciprocal temperature suggests an Arrhenius model, the electrical conductivity increase with increasing AuNPs contents confirm that AuNPs as promising candidate nanofiller for improving the electrical properties of CMC.