Cellulose

Cellulose

Cellulose (Latin cellula, “little cell”), complex carbohydrate, the chief constituent of the cell wall of all plant cells. In plants, cellulose is normally combined with woody, fatty, or gummy substances. With some exceptions among insects, true cellulose is not found in animal tissues. Microorganisms in the digestive tracts of herbivorous animals break down the cellulose into products that can then be absorbed. Cellulose is insoluble in all ordinary solvents and may be readily separated from the other constituents of plants. Depending on its concentration, sulfuric acid acts on cellulose to produce glucose, soluble starch, or amyloid; the last is a form of starch used for the coating of parchment paper. When cellulose is treated with an alkali and then exposed to the fumes of carbon disulfide, the solution yields films and threads. Rayon and cellophane are cellulose regenerated from such solutions. Cellulose acetates are spun into fine filaments for the manufacture of some fabrics and are also used for photographic safety film, as a substitute for glass, for the manufacture of safety glass, and as a molding material. Cellulose ethers are used in paper sizings, adhesives, soaps, and synthetic resins.

With mixtures of nitric and sulfuric acids, cellulose forms a series of flammable and explosive compounds known as cellulose nitrates, or nitrocelluloses. Pyroxylin, also called collodion cotton, is a nitrate used in various lacquers and plastics; another, collodion, is used in medicine, photography, and the manufacture of artificial leather and some lacquers. A third nitrate, guncotton, is a high explosive.