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Preparation of PVDF/PMMA/PZT Nanocomposites and Studying of Its Crystal Structure, Morphology and Electrical Properties

Omoomi, Ali | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54724 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Frounchi, Masoud
  7. Abstract:
  8. Polyvinylidene fluoride is highly regarded by researchers due to its piezoelectric properties, mechanical properties, chemical and thermal stability and biocompatibility. This thermoplastic polymer has a semi-crystalline structure and, depending on the crystallization conditions, has five distinct crystalline phases α, β, γ, δ and ε. The β, γ and δ phases are electroactive, and among them, the β phase has high piezoelectric activity due to its high dipole moment. This study focuses on increasing the amount of β phase in polyvinylidene fluoride and increasing its piezoelectric property. Polyvinylidene fluoride is highly miscible with oxygen containing polymers such as polymethyl methacrylate. Polymethyl methacrylate is a non-crystalline polymer, hard, transparent, solvent resistant and has optical properties. The blend of this polymer with polyvinylidene fluoride causes the formation of β phase in its crystalline structure and thus increases its electrical properties. Lead zirconatetitanate is a ceramic filler with a very high dielectric constant and excellent piezoelectric properties, and its addition to the polyvinylidene fluoride polymer matrix also causes the formation and increase of phase β. In this study, nanocomposite films of polyvinylidene fluoride/polymethyl methacrylate/lead zirconatetitanate were prepared by solution blending with dimethylformamide solvent. The results of Fourier transform infrared spectroscopy and X-ray diffraction analysis indicated that α, β and γ phases were present in the nanocomposites and that lead zirconatetitanate nanoparticles appeared in the role of nucleating agent and accelerated polyvinylidene crystallization. The results of field emission scanning electron microscopy showed that when the weight percentage of polyvinylidene fluoride is higher than polymethyl methacrylate, the two polymers are well compatible and form a uniform and homogeneous phase. Good distribution and dispersion of nanoparticles was also observed in the nanocomposite films. The results of conductivity and piezoelectric analysis showed that the polyvinylidene fluoride/polymethyl methacrylate/lead zirconatetitanate nanocomposite with a weight percentage of 75/25/8 has the highest specific conductivity and the best piezoelectric property
  9. Keywords:
  10. Polyvinylidene Fluoride (PVDF) ; Poly Methylmethacrylate ; Lead Zirconate Titanate (PZT) ; Piezoelectric ; Beta Phase ; Crystalline Structure ; Morphology ; Electrical Properties

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