Study of chitosan with different degrees of acetylation as cardboard paper coating.

The biodegradability of chitosan is significant for packaging systems. Another relevant property of chitosan is its degree of acetylation (DA), which affects other properties, such as crystallinity and hydrophobicity. The DA can be modulated by chitin deacetylation or even chitosan reacetylation. The novelty of this paper is the application of reacetylated chitosan as a coating for cardboard paper surfaces to improve the barrier and mechanical properties of the paper. Chitosan with 2% DA was reacetylated to yield chitosan with 48% DA. Both samples were applied as cardboard paper coating, and the coated materials were characterized. The paper-film system of chitosan with 2% DA had better water barrier and mechanical resistance. Heterogeneous deacetylation of chitin reduced the solubility of chitosan because molecular groups were distributed in blocks, increasing the hydrophobicity of the polymer.