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High strength of
poly(acrylic acid)-chitosansilica hydrogel composites
Presenter: Feng-Chien Hsu
Adviser: Professor Hong-Ru Lin
Date: 2009/11/21
Introduction
• Joint pain is a major cause of disability in middleaged and older people. Joint’s 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.
• 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.
Materials
poly(acrylic acid)-chitosan-silica(PAA-Ch-Si) hydrogels
•
•
•
•
•
•
Acrylic acid (AAc)
Chitosan
Silica
Ammonium peroxodisulfate (APS)
N,N’-methylenebisacrylamide (NMBA)
Glutaraldehyde (GA)
Preparation
Acrylic acid
Chitosan
Distilled water
APS、NMBA and GA
Stirred until complete
dissolved
Injected to mold
Exposed to UV-light
Hydrogel
Results and discussion
Table.1 Mechanical properties of PAA, PAA-Ch, PAASi and PAA-Ch-Si hydrogels
Unit
Elastic modulus
(MPa)
Max stress
(MPa)
Max strain
(%)
Toughness
(J)
Cross-link density
(×10-5 mole/cm3)
PAA
0.91±0.14
4.94±1.44
29.33±3.70
0.76±0.08
0.195±0.047
PAA-Ch
1.44±0.18
6.31±0.50
32.01±1.44
1.47±0.16
0.204±0.041
PAA-Si
1.49±0.16
8.92±1.22
25.92±1.43
1.99±0.68
0.764±0.15
PAA-Ch-Si
2.50±0.28
42.26±3.63
25.23±0.59
5.23±1.48
2.293±0.06
Sample
(a) PAA
(c) PAA-Si
(b) PAA-Ch
(d) PAA-Ch-Si
Fig.1 Scanning electron microscope of PAA, PAA-Ch, PAA-Si and PAA-Ch-Si hydrogels
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.
References
[1] Junping Zhang, Qin Wang, Aiqin Wang, Synthesisand characterization of
chitosan-g-poly(acrylic acid)/attapulgite superabsorbent composites,
Carbohydrate Polymers, 367–374 (2007) 68.
[2] Kyung Min Park, Sang Young Lee, Yoon Ki Joung, Jae Sik Na, Myung
Chul Lee, Ki Dong Park , Thermosensitive chitosan–Pluronic hydrogel as
an injectable cell delivery carrier for cartilage regeneration, Acta
Biomaterialia, 1956–1965 (2009) 5.
[3] Hockin H.K. Xu, Douglas T. Smith, Carl G. Simon, Strong and bioactive
composites containing nanosilica-fused whiskers for bone repair,
Biomaterials, 4615–4626 (2004) 25.
[4] Xiaomei Shi, Shimei Xu, Jiantao Lin, Shun Feng, Jide Wang* “Synthesis
of SiO2-polyacrylic acid hybrid hydrogel with high mechanical properties
and salt tolerance using sodium silicate precursor through sol–gel process”,
Materials Letters,527–529 (2009) 63.
[5] Jian Ping Gong, Yoshinori Katsuyama, Takayuki Kurokawa, Yoshihito
Osada ”Double-network hydrogels with extremely high mechanical
strength”, Advanced Materials, 1155-1158(2003) 14.
[6] C. Schiraldi, A. D’Agostino, A. Oliva, F. Flamma, A. De Rosa, A. Apicella,
R. Aversa and M. De Rosa, Biomaterials, 3645 (2004) 25.