| Summary: | 碩士 === 國立成功大學 === 化學工程研究所 === 85 ===
Chitosan is prepared by chemical N-deacetylation of chitin. Chitin is, after cellulose, the second most abundant naturally occuring polysaccharides. The effect of some sulfated derivatives of chitosan on several blood-coagulant factors was examined in comparision with those of heparin.
In this study, the chitosan membrane surface was sulfonated by reactions with pyridine-sulfur trioxide (SO3/pyridine complex) in H2O solution and N,N-Dimethylformamide-sulfur trioxide (SO3/DMF complex) in DMF. After modification, the samples are analyzed through ESCA, ATR-FTIR, SEM, EA etc., to examine their surface and bulk characteristics.
The surface reaction of pyridine-sulfur trioxide in aqueous acid medium is readily to yield N,O-sulfated chitosan with cationic NH3+ groups. After being neutralized with low sodium hydroxide concentration solution, the surface has shown to induce the least degree of platelets activation and the least amount of platelets adhesion as well.
On the other hand, when it is utilized in an aqueous alkaline medium at pH10.5, pyridine-sulfur trioxide has been found to sulfonate the amino group only. Although the degree of sulfonation is lower than the samples above by far, the N-sulfated chitosan also has an prominent effect to reduce the adhesion and activation of platelets.
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