In this study, poly(ethylene glycol) dimethacrylate (PEGDMA) was used to crosslink chitosan (CS) chains selectively at the C-6 position of pyranose. Before the crosslinking reaction, the amino group at the C-2 position was protected by reaction with phthalic anhydride (PA) to form phthaloylated chitosan (PACS). From the results of elemental analysis, the degree of substitution was calculated to be 0.88, indicating most amino groups were converted to phthalimide groups. Subsequently, 3-isopropenyl-α,α-dimethylbenzyl isocyanate (TMI), a vinyl compound containing an isocyanate group, was used to react with the PACS, preferentially with the hydroxyl group at the C-6 position. The reaction with TMI thus provided multiple double bonds along the CS chain. The phthalimide group was then reduced to the original amino group by the hydrazine solution at 80oC. Finally, the vinyl CS was crosslinked with PEGDMA at the C-6 position by a UV-initiated free-radical polymerization. FTIR and NMR were used to analyze the chemical structure of PEG-crosslinked CS. Thermal and mechanical properties of the PEG-crosslinked CS membrane were measured and related to their structures. The PEGDMA-crosslinked CS membrane has potential applications as a biomedical material.
Relation:
10th International Conference of the Asian Pacific Chitin Chitosan Symposium, pp. 249
