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Antistatic Polyurethane Coating Containing Zirconia Nanoparticles

Najafkhani, Hossein | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48985 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Dolati, Abolghasem
  7. Abstract:
  8. In this study, antistatic waterborne polyurethane coating containing zirconia nanoparticles is made and applied on 304 stainless steel substrates at weight percentage of 0.66, 1.3, 3, 4.5 and 6% zirconia nanoparticles. For synthesis of hydrophilic isocyanate prepolymer, isocyanate prepolymer is modified by hydrophilic polyethylene glycol with molecular weight 600, 1000 and 4000. For ensuring of modification condition and stability of hydrophilic isocyanate prepolymer in aqua solution, FTIR and stability tests are employed, respectively. In order to create antistatic properties of these coatings, semi - conductive zirconia nanoparticles are used. To improve the distribution of zirconia nanoparticles in the polymer matrix and making suitable interaction between nanoparticles and coating, surface modification by APTES silane group is applied on nanoparticles. For ensuring of surface modification of nanoparticles reaction and stability in polymer matrix, FTIR and stability in organic solution tests are also employed, respectively. Forever, the effect of adding zirconia nanoparticles to waterborne polyurethane coatings on antistatic properties is studied by means of surface electrical measurement. For investigation of surface morphology and zirconia nanoparticles distribution, FE-SEM is used. Thickness of coating was measured by thickness gauge and the mid-size is found to be 40 µm. pull-off test is used for investigation of adhesion strength of coating. Roughness and surface topography of nanoparticles are also studied by AFM. FTIR test results showed that modified hydrophilic prepolymer by polyethylene glycol with molecular weight of 600 and NCO/OH=2, represents the best results and disperse easily in aqua solution and this synthesis prepolymer is used to be waterborne polyurethane prepolymer. Moreover, FTIR and FE-SEM results of coating showed that surface modification with silane group is lead to a uniform distribution of zirconia nanoparticles in polymer matrix. Also the size of modified zirconia nanoparticles is measured to be in range of 50 to 110 nm. Adhesion test results showed that the adhesion strength is increased by adding zirconia nanoparticles up to 3%wt and adhesion strength is decreased by adding zirconia nanoparticles in the range of 3%wt to 6%wt. Moreover, the result of surface electrical resistance test showed that adding zirconia nanoparticles leads to a decrease in surface electrical resistance and polyurethane coating containing 6%wt of zirconia nanoparticles has surface electrical resistance of 9.1 × 109 Ω/m2 which is a good antistatic coating
  9. Keywords:
  10. Polyethylen Glycol (PEG) ; Polyurethane Coating ; Water Borne Polyurethane Coating ; Hydrophilic Isocyanate Prepolymer ; Zirconia Nanoparticles ; Aminopropyl Trioethoxy (APTES)Silane Group

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