The cross-linked chitosan coating increased both the
tensile strength and the elastic modulus, and reduced the
elongation at break of the sheets when compared with the
control sheet. With the cross-linking of the coating, the
macromolecules are covalently linked, forming a three-
dimensional network and reducing the mobility of the
chains, which makes the sheets less
fl
exible and more
resistant. Kittur et al.
[20]
reported that cross-linked chitosan
films showed an 18% reduction in elongation and 33%
increase in tensile strength when compared to non-cross-
linked films.