Presenter: FengChien Hsu

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High strength of poly(acrylic acid)-chitosan-sili
ca hydrogel composites

• Presenter Feng-Chien Hsu
• Adviser Professor Hong-Ru Lin
• Date 2009/11/21

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Introduction

• Joint pain is a major cause of disability in
  middle-aged and older people. Joints cartilage
  due to primary osteoarthritis or from trauma
  causing loss of cartilage.
• Chitosan is one of the most abundant biomass
  sources in the world. Its chemical structure is
  analogous with diverse glycosaminoglycans found
  in articular cartilage.

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• Nano-sized silica particles were recently fused
  onto ceramic whiskers and used as fillers to
  reinforce dental resin to extend their use to
  large stress-bearing restorations.
• Most of hydrogels derived from either natural or
  synthetic sources suffer from lack of mechanical
  strength. In this study, high strength
  poly(acrylic acid)-chitosan-silica(PAA-Ch-Si)
  hydrogels were prepared by UV polymerization for
  cartilage repair.

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Materials
poly(acrylic acid)-chitosan-silica(PAA-Ch-Si)
hydrogels

• Acrylic acid (AAc)
• Chitosan
• Silica
• Ammonium peroxodisulfate (APS)
• N,N-methylenebisacrylamide (NMBA)
• Glutaraldehyde (GA)

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Preparation
Acrylic acid
APS?NMBA and GA
Distilled water
Chitosan
Stirred until complete dissolved
Injected to mold
Exposed to UV-light
Hydrogel
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Results and discussion
Table.1 Mechanical properties of PAA, PAA-Ch,
PAASi and PAA-Ch-Si hydrogels
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Fig.1 Scanning electron microscope of PAA,
PAA-Ch, PAA-Si and PAA-Ch-Si hydrogels
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Conclusion

• The PAA-Ch-Si hydrogel had highest mechanical
  strength(42 MPa) among the others. Its elastic
  modulus, toughness and cross-link density were
  all higher than other hydrogels.
• The SEM image shows that pores were distributed
  inside the PAA-Ch-Si hydrogel, which is expected
  to absorb body fluid once implanted.

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References
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Synthesisand characterization of
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T. Smith, Carl G. Simon, Strong and bioactive
composites containing nanosilica-fused whiskers
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