Loading...

Kheirabadi, Malihe | 2009

771 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 40015 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Pourjavadi, Ali; Zohurian Mehr, Mohammad Jalal
  7. Abstract:
  8. Polyampholyte hydrogels are hydrophilic networks that contain both positively- and negatively-charged functional groups on their structure. Polysulfobetaines are the most important type of polyampholytes, which have been extensively studied. However, these hydrogels exhibited poor gel strength causing limitation of their applications. Consequently, much attention has been focused on the preparation of nanocomposite hydrogels with high gel strength and lower cost using organomodified clays. In this project, Novel polyampholytic superabsorbing nanocomposites based on the zwitterionic sulfobetaine monomer [3-(methacrylamido)propyl)]dimethyl(3-sulfopropyl) ammonium hydroxide (MPDSAH) were synthesized through in-situ polymerization in aqueous solution with different contents of an organo-modified clay (OMMT, Cloisite 30B). Structural, thermal and thermomechanical properties of hydrogels were characterized by FT-IR, XRD, TGA and DMTA, respectively. Swollen gel strength of hydrogels was determined by a rheological method. Storage modulus of the hydrogels was considerably improved in comparison with its the clay-free counterpart. The nanocomposite hydrogel containing 15% OMMT possessed the highest gel strength. In addition, thermal stability of hydrogels of containing clay was more than clay-free hydrogel. The glass transition temperature was increased from 58.4 to 67.0 oC for the clay-free and nanocomposite hydrogel containing 8% OMMT, respectively. The swelling behavior of the hydrogel in various salt solutions was investigated. Anti-polyelectrolyte behavior was observed with enhancement of concentration of mono- and multi-valent salts. Swelling in the various pH media was nearly pH-independent over a wide range of pH.

  9. Keywords:
  10. Hydrogel ; Nanocomposite ; Superabsorbent ; Sulfobetain ; Zwitter-Ion

 Digital Object List

 Bookmark

No TOC