Cellulose is a polysaccharide made up of 3,000 or more glucose units and is a complex carbohydrate. The most abundant of all naturally occurring organic molecules, cellulose is the basic structural component of plant cell walls, accounting for around thirty percent of all vegetable matter. Although cellulose is indigestible by humans, it provides a food source for herbivorous animals because it is retained long enough for microorganisms in the alimentary tract to digest it; protozoans in the guts of insects such as termites also digest cellulose. Cellulose is processed to make sheets and fibres, and it is chemically changed to make plastics, photographic films, and rayon, among other things. Other cellulose derivatives are employed in adhesives, explosives, food thickening agents, and moisture-proof coatings, among other applications.
Anselme Payen, a French scientist, discovered cellulose in 1838 after isolating it from plant matter and determining its chemical formula. Hyatt Manufacturing Company employed cellulose to create the first viable thermoplastic polymer, celluloid, in 1870. Then, Cellophane was created in 1912, while rayon also known as fake silk was first produced from cellulose in the 1890s. In 1920, Hermann Staudinger discovered the polymer structure of cellulose. Kobayashi and Shoda were the first to chemically synthesize the molecule without the assistance of any biologically derived enzymes, in the year 1992.
Properties of Cellulose:
Most of cellulose’s properties are influenced by its chain length or degree of polymerization, which refers to the amount of glucose units in each polymer molecule. Wood pulp cellulose has a total chain length of three hundred to seventeen hundred units, while cotton and other plant fibres, as well as bacterial cellulose, have a chain length of eight hundred to ten thousand units. Cellodextrins are cellulose-derived molecules with very short chain lengths that are soluble in water and organic solvents, unlike long-chain cellulose. (C6H10O5)n is the chemical formula for cellulose, where n denotes both the degree of polymerization and the number of glucose groups.
Plant-derived cellulose is typically mixed with hemicellulose, lignin, pectin, and other compounds, whereas bacterial cellulose is nearly pure, has a significantly higher water content, and has a significantly better tensile strength due to longer chain lengths. Fibrils of cellulose have crystalline and amorphous areas. Mechanical treatment of cellulose pulp, typically aided by chemical oxidation or enzymatic treatment, can produce semi-flexible cellulose nanofibrils ranging in size from 200 nm to 1 m in length, depending on the treatment intensity. Cellulose pulp can also be treated with a strong acid to hydrolyze the amorphous fibril regions, resulting in short and stiff cellulose nanocrystals with a length of a few hundred nanometers. Due to factors like their self-assembly into cholesteric liquid crystals, formation of hydrogels or aerogels, application in nanocomposites with superior thermal and mechanical properties, and use as Pickering stabilisers for emulsions, these nanocelluloses are of significant technological importance.
Applications Of Cellulose:
The following are few of the numerous applications of cellulose:
1.Cellulose is the most common component of paper, paperboard, and card stock. Insulation paper for transformers, cables, and other electrical equipment also have cellulose as a key component to them.
2. Textile fibres are made up primarily of cellulose. By volume, cotton and synthetics nylons each account for around 40 percent of the market. Other plant fibres such as jute, sisal, and hemp account for roughly 20 percent of the market. Rayon, cellophane, and other regenerated cellulose fibres account for only a small percentage of the total which is 5 percent.
3. Microcrystalline cellulose and powdered cellulose are employed as inactive fillers in medicine tablets, while a wide range of soluble cellulose derivatives are employed in processed foods as emulsifiers, thickeners, and stabilisers. Cellulose powder, for example, is used in processed cheese to keep the package from caking. Cellulose is an indigestible component used for texture and bulk that may aid in defecation. It is found naturally in some foods and as an additive in manufactured foods.
4. As an alternative to the usage of plastics and resins, hydroxyl bonding of cellulose in water provides a sprayable, moldable material. Water and fire resistance can be added to recyclable material. It has enough strength to be used as a building material. Cellulose insulation derived from recycled paper is gaining popularity as a more environmentally friendly building insulation material. As a fire retardant, it can be treated with boric acid.
5. Cellulose can be made into cellophane, which is a thin translucent film. Until the mid-1930s, it was the foundation material for celluloid, which was used for photographic and motion picture films. Water-soluble adhesives and binders such as methyl cellulose and carboxymethyl cellulose, which are utilised in wallpaper paste, are made from cellulose. Cellulose is also utilised to manufacture sponges that are hydrophilic and absorbent. The raw material for nitrocellulose, which is used in smokeless gunpowder, is cellulose.
6. Cellulose derivatives, such as microcrystalline cellulose (MCC), offer the advantages of retaining water, acting as a stabilizer and thickening agent, and reinforces the medicine or tablet.