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Synthesis of Double Network Hydrogels Based on Chitosan, Alginate, and Poly (Vinyl Alchohol) with High Mechanical Properties and Investigation of Their Biocompatibility

Tavakkoli, Elham | 2015

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48771 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Pourjavadi, Ali
  7. Abstract:
  8. Double network (DN) hydrogels are a new interpenetrate polymer network (IPN) that are usually contain about 60-90 % water. Despite of this amount of water, they are though and strong. DN hydrogels comprise of two networks, the first one as the brittle gel, is generally high density crosslinked and the second one, the loose and stretchable network, is loosely crosslinked or even without crosslinking. Therefore, we used cationic polymer, chitosan, and anionic polymer, alginate, as the first networks, therefore, we used sodium phosphate for physical crosslinking of chitosan, and calcium chloride as the physical crosslinking agents for alginate network. Also, poly (vinyl alcohol) (PVA), as the second network, was crosslinked by using freeze-thaw processes. To improve the interaction of two networks, plasticizers such as glycerol, sucrose and etc., had been added. So, we used honey as a plasticizer because it is mainly composed of fructose, glucose, maltose, and sucrose that are all biocompatible. Nontoxicity and biocompatibility of these materials make the synthesized DN hydrogel possible to use in bio applications such as wound dressing, drug delivery, and tissue engineering. We characterized the nature of the synthesized chitosan/PVA and alginate/PVA films by FT-IR spectroscopy and TGA test and their mechanical performance was also investigated by using mechanical tests such as tensile and compression. Our data suggests that the fracture energy of hydrogels can be greatly increased by combining weak and strong crosslinks. The combination of relatively high stiffness, high toughness and recoverability of stiffness and toughness, along with an easy method of synthesis, make these materials ideal candidates for further investigation
  9. Keywords:
  10. Poly Vinyl Alcohol ; Alginate ; Chitosan ; Biocompatibility ; Mechanical Properties ; Double Network Hydrogel

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