Synthesis of Polyurea for Use in the Coating Process

Rouzbahani, Amir Reza | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55056 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Mousavi, Abbas
  7. Abstract:
  8. To produce polyurea, a secondary or higher amine must be combined with a diisocyanate. For this purpose, we first combined diethylenetriamine, and hexamethylene diisocyanate, which did not have good mechanical properties due to the aliphatic nature of the molecules. Then, instead of hexamethylene diisocyanate, we used MDI, which was mixed using a mechanical mixer but became a paste that was not suitable for coating applications. To reduce the viscosity of MDI, propylene carbonate was added to improve mixing, but the gel time also increased. Because the solvent was non-polar and the amine was polar, it was decided to add the solvent, amine, and polyvinyl alcohol as surfactants to allow faster mixing, but a side reaction took place in which the product contained the ol and amine, functional groups. Then, using a combination, different percentages of resin were obtained that reacted quickly with MDI and were exothermic. Therefore, in order to control the temperature and prevent the degradation of the MDI sample, it was added to polypropylene carbonate to obtain a suitable final product.For further investigation, FTIR and tensile tests were used to examine the polyurea functional group as well as the physical condition of the coating. For mechanical testing, the final product was used on building materials, which increased the acceptable mechanical strength. Finally, the UV test showed stability in environmental conditions for the best percentage composition.
  9. Keywords:
  10. Coating ; Synthesis ; Gel Time ; Polyurea ; Methylene Diamine ; Methylene Diphenyl Diisosyanate

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