الفهرس 
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Abstract
The present thesis includes preparation, characterization and evaluation of the structural changes of the prepared systems. The present study can be divided into three basic sections. Section (I) concerns ’’Structural properties and preparation of pure nanoparticles (selenium nanoparticles)’’ where SeNPs were prepared via chemical reduction method. In this section Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV/Vis) and transmission electron microscopy (TEM) were employed to test the physical and chemical characteristics of pure nanoparticles, where TEM confirms formation of nanoparticles with diameter range between 25-50 nm. FTIR confirmed chemical structure of SeNPs. UV/Vis. was used to study optical properties. Section (II) concerns ’’Structural properties and preparation of pure polymers (Polyvinyl alcohol (PVA) and Sodium alginate (SA)’’ in which films of each polymer were prepared via casting solution technique method. In this section x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were employed to test the physical and chemical characteristics of pure polymers, while ultraviolet-visible (UV/Vis) was used to study optical properties, anti-microbial test was revealed biocompatibility of each polymer. Section (III) concerns ”Preparation and testing chemical and physical properties besides antimicrobial activity of films of pure PVA/SA blend and modified PVA/SA blends with different contents of SeNPs. (PVA/SA and SeNPs/PVA/SA) were characterized by the same techniques of section (II) besides scanning electronic microscopy (SEM). FTIR confirmed interaction between PVA and SA in their blend trough formation of hydrogen bond and showed no shifts when adding SeNPs. UV-Vis and optical energy gap confirmed improving of optical and electrical properties of the blend when increasing content of SeNPs. XRD revealed semi crystallilnity of the blend and confirmed that SeNPs had no effect on this nature. Miscibility of the prepared PVA/SA blend and uniform dispersion of SeNPs in the tested samples were confirmed by SEM. The PVA/SA blend showed antimicrobial activity which increased by increasing SeNPs content to a specific one (8 ml) which is recommended. Concluding that blending between PVA and SA improves physical and chemical properties. SeNPs add the unique properties of nanoparticles to the polymeric blend. This opens various fields to be applied in.