What is Chitosan
Chitosan is deacetylated derivative of Chitin,linear polysaccharides composed of varying amounts of linked residues of "N-acetyl-2 amino-2-deoxy-D-glucose (glucosamine, GlcN)" and "2-amino-2-deoxy-D-glucose (N-acetyl-glucosamine, GlcNAc)" residues.Commercial chitosan products were produced from chemical deacetylation of chitin from crustacean sources (Ex: crab shells, shrimp shells).
Chitosan is the only polycation in nature and its charge density depends on the degree of deacetylation and pH of the media.The solubility of the Chitosan depends on the acetylation degree and molecular weight.Chitosan with higher MW are only soluble in acidic aqueous media even at high deacetylation degrees.The poor solubility of chitosan in alkaline aqueous solution severely limits its range of applications.

The viscosity of Chitosan
Chitosan viscosity depends on the molecular weight of the polymer and deacetylation degree and decreases as the molecular weight of chitosan is reduced.The viscosity of chitosan is influenced by its molecular weight.

Chelation Property of Chitosan
Attributing to the presence of large number of amino groups on chitosan molecular chains, Chitosan can also be used in water processing engineering. Chitosan molecules are known to chelate anionic dyes in waste dye solution and flocculate them out.It has also been found that the chitosan and its derivatives can remove phosphorus, heavy metals, and oils from water.