Investigations of the effects of glyoxal cross-linking on the structure and properties of chitosan fiber

The effect of glyoxal cross-linking on the structure and properties of chitosan fiber has been studied using different techniques. Swelling results showed that the cross-linking process can be described by a formula such as: S=79.24−5.05C+0.24C2 (S, swelling degree; C, glyoxal concentration). WAXD indicated that the cross-linking affects on the chitosan fibers at reducing of its crystallinity, e.g. from 34.7 to 27.2% for this case prepared fiber. Comparing to uncross-linked chitosan fiber, DSC and polarizing microscopy further indicated that the change of the crystal structure for cross-linked chitosan fiber is exactly affecting to the thermal properties. Additionally, SEM photographs showed that the cross-linking seems to play a role to smooth the surface of fiber due to the surface of original chitosan fiber observed roughly.