Chitin is a natural material that is found in several different species of animals and insects. Primarily used as a structural material by the animals, chitin is also a raw material for a product called chitosan, which is useful for human industrial purposes. After a factory extracts chitin from sources like shrimp shells, it is treated to form the similar molecule chitosan, which has applications in such diverse fields as the cosmetics industry and water processing plants.
As chitin is commonly found in a variety of animals, the extraction of chitin and chitosan form an industry that is renewable. Byproducts of fishing, that would otherwise go to landfill, may be suitable for chitin and chitosan processing. Typically, shells of shrimp, crabs and lobster yield chitin for this process.
In a living organism, chitin acts as structural material, to help keep the body of the organism safe and allow the various parts of the body move around independently. Chemically, the molecule is a polysaccharide, which is a long chain of sugars, one after the other. Chitin and chitosan share much of the same molecular formula, with a few differences.
Chitosan is basically chitin with a few segments of atom groups removed. These groups are called acetyl groups, and are individually made up of two parts. One carbon atom attached to three hydrogen atoms makes up one portion, and the other bit of the acetyl group contains another carbon and an oxygen atom. Altogether, then, the acetyl group is represented by the chemical formula Ch3CO-.
Losing the acetyl groups is the only chemical difference between chitin and chitosan, but it also affects the characteristics of the substance. Chitosan is more easily dissolvable in weak acid solutions, which can be helpful in solutions such as cosmetics. In cosmetics, the main application of chitosan is that it helps to keep water in the product, and helps to form a film over skin that keeps water and other essential molecules at the desired point of action. Shampoos, facial creams and nail polishes can all contain chitosan.
Filtering debris and microbial contamination out of water is another application of chitosan, and products that contain it may also have insect repellent qualities. Chitin and chitosan may also have applications in medical fields, as the molecules tend to be accepted by the human immune system more easily than some other molecules. Dressings on wounds, contact lenses and dissolvable sutures are some examples of the applications of these substances.