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Preparation of Antibacterial Silver, PVA, Na Alginate Nanocomposites Via Gamma Irradiation

Eghbalifam, Naimeh | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 45500 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Frounchi, Masoud; Dadbin, Susan
  7. Abstract:
  8. In this research, polyvinyl alcohol/ sodium alginate/ nano silver nanocomposite films were fabricated by solution casting method via gamma irradiation. The purpose of using gamma radiation was reduction of silver nitrate and synthesis of silver nanoparticles. Formation of silver nanoparticles was proved by ultra violet- visible spectroscopy (UV-Vis) and x-ray diffraction (XRD) tests. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) were used to study morphology, size and distribution of silver nanoparticles. Chemical structure, thermal behavior and mechanical properties of nanocomposites were characterized by fourier transform infrared spectroscopy (FTIR), differential scanning calorimetery (DSC) and tensile tests. Also, silvar release and antibacterial properties of nanocomposites were investigated using agar diffusion method. UV-Vis and XRD results demonstrated that spherical silver nanoparticles were synthesized even at lower irradiation dose of 5 kGy. By increasing irradiation dose, more nanoparticles were synthesized and their size was decreased. These results were confirmed by SEM images. Appropriate interaction of polyvinyl alcohol and sodium alginate can be seen in the images which agree very well with FTIR spectroscopy results. Moreover, comparing these images with DLS test results indicate good performance of polyvinyl alcohol as a stabilizer. According to DSC test results, by the addition of sodium alginate to polyvinyl alcohol and increasing silver nanoparticles, the melting peak shifted to lower temperature and crystallinity percent was decreased. Addition of sodium alginate leads to remarkable increase in young's modulus and decrease in elongation at break. Adding silver nanoparticles up to the 0.5%, improves the mechanical properties of nanocomposite but with further increasing of it, modulus decreased. The results showed strong antibacterial activity against Staphylococcus aureus and Escherichia coli already at the lowest addition level of silver nanoparticles
  9. Keywords:
  10. Nanocomposite ; Poly Vinyl Alcohol ; Sodium Alginate ; Silver ; Gamma Rays

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