Materials Based on Chitin and Chitosan

In this chapter, the characterization and main properties of chitin and chitosan are described to indicate the advantage of such polysaccharides. The main development in the field of materials concerns chitosan, which is solubilized in acidic conditions whereas chitin is difficult to transform. Chitin is a semi-crystalline polysaccharide that can be processed as fibres or membranes with good mechanical properties due to the cooperative hydrogen bond network formed in the solid state. It has some hydrophilic characteristics and antimicrobial properties. It is also used in composite materials as fibres to reinforce synthetic or natural polymers. Chitosan is more developed due to its solubility in acidic media; it is easy to process under different conformation: fibre, film, sponge, bead and so on. It may be blended with other polymers, especially in electrostatic complexes with alginate or hyaluronan. Numerous application domains are described for these chitin / chitosan-based materials in the literature but mainly in biomedical, pharmaceutical, cosmetics and packaging. The important attributes of these natural polymers are mainly their biocompatibility, antimicrobial properties and biodegradability / resorbability in the body. Another advantage of chitosan is that specific derivatives may be prepared due to the presence of free reactive -NH2 groups on the C-2 position of the D-glucosamine unit.