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Synthesis and characterization of pH-sensitive hydrogels based on chitosan and D,L-lactic acid

✍ Scribed by Xin Qu; Anders Wirsén; Ann-Christine Albertsson

Publisher
John Wiley and Sons
Year
1999
Tongue
English
Weight
270 KB
Volume
74
Category
Article
ISSN
0021-8995

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✦ Synopsis

Novel pH-sensitive physically crosslinked hydrogels were synthesized by grafting D,L-lactic acid (LA) onto the amino groups in chitosan (CS) without a catalyst. The structures of these graft copolymers were analyzed by FTIR and X-ray measurements. Degree of substitution, side-chain length, and yield of copolymers were evaluated from 1 H-NMR, salicylaldehyde, and elemental analysis. The crystallinity of chitosan gradually decreased after grafting, since the side chains substitute the ONH 2 groups of chitosan randomly along the chain and destroy the regularity of packing between chitosan chains. Water uptake of the hydrogels was investigated as a function of side-chain length and degree of substitution. The influence of pH and salt concentration on the swelling behavior of the hydrogels was determined and interpreted.

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