Rheological Characterization of in Situ Crosslinkable Hydrogels Formulated from Oxidized Dextran and N-Carboxyethyl Chitosan
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- 作者：Lihui Weng ; Xuming Chen ; Weiliam Chen
- 刊名：Biomacromolecules
- 出版年：2007
- 出版时间：April 2007
- 年：2007
- 卷：8
- 期：4
- 页码：1109 - 1115
- 全文大小：341K
- 年卷期：v.8,no.4(April 2007)
- ISSN：1526-4602
文摘
The gelation kinetics of an in situ gelable hydrogel formulated from oxidized dextran (Odex) and N-carboxyethylchitosan (CEC) was investigated rheologically. Both Schiff base mediated chemical and physical crosslinkingaccount for its rapid gelation (30-600 s) between 5 and 37 
C. The correlation between gelation kinetics andhydrogel properties with Odex/CEC concentration, their feed ratio, and temperature were elucidated. The gelationtime determined from crossing over of storage moduli (G') and loss moduli (G' ') was in good agreement withthat deduced from frequency sweeping tests according to the Winter-Chambon power law. The power lawexponents for a 2% (w/v) Odex/CEC solution (ratio 5:5) at the gel point was 0.61, which is in excellent agreementwith the value predicted from percolation theory (2/3). Temperature dependence of gelation time for the samehydrogel formulation is well-described by an Arrhenius plot with its apparent activation energy calculated at 51.9kJ/mol.
C. The correlation between gelation kinetics andhydrogel properties with Odex/CEC concentration, their feed ratio, and temperature were elucidated. The gelationtime determined from crossing over of storage moduli (G') and loss moduli (G' ') was in good agreement withthat deduced from frequency sweeping tests according to the Winter-Chambon power law. The power lawexponents for a 2% (w/v) Odex/CEC solution (ratio 5:5) at the gel point was 0.61, which is in excellent agreementwith the value predicted from percolation theory (2/3). Temperature dependence of gelation time for the samehydrogel formulation is well-described by an Arrhenius plot with its apparent activation energy calculated at 51.9kJ/mol.