Introduction to Chitin, Chitosan, and Alginate Fibers
Chitin is a polymer made from units of N-acetyl glucosamine as shown in Fig. 23.1. Chitin is the structural unit that provides strength to most invertebrates and is one of the most common biopolymers found in nature. Unlike most other polysaccharides, chitin contains about 6.9 % nitrogen which makes it useful as a chelating agent and also for various applications in the pharmaceutical, biomedical, paper, textile, photographic, and other applications. Chitin is also found in bacteria and fungi. In its native form, chitin is insoluble in common solvents and therefore has limited applications. Typically, chitin exists with an average molecular weight of 1.036 × 106 to 2.5 × 106 Da. Generally, chitin is deacetylated and obtained as chitosan which is soluble in aqueous acetic acid. Fibers have been obtained from chitin, chitosan, and several other chitin derivatives.