Grafting Modification of Chitosan

Chitosan, a natural polymer obtained by chitin via alkaline deacetylation, is the only cationic polysaccharide in nature. It has versatile properties, such as biodegradability, biocompatibility, hemostatic behavior, and promotion of wound healing. Chitosan was widely used in different fields. However, there are also many disadvantages for chitosan and its derivatives, such as lower mechanical property, higher price, and not prominent performance. Chitosan is also a very versatile material. It is easy to be modified by new functional groups grafted on the skeleton of it. In the current chapter, we want to introduce the method for grafting modification of chitosan, such as acylation, alkylation, hydroxyalkylation, carboxyalkylation, quaternization, thiolation, phosphorylation, sulfation, and graft copolymerization. We also want to introduce the progress for the application of the above derivativs in different fields.