The existence of cellulose as the common material of plant cell walls was first recognized by Anselm Payen in 1838. It occurs in almost pure form in cotton fiber and in combination with other materials, such as lignin and hemicelluloses, in wood, plant leaves and stalks, etc. Although generally considered a plant material, cellulose is also produced by some bacteria.

It has been accepted for many years that cellulose is a long chain polymer, made up of repeating units of glucose, a simple sugar. In the early 1900s, cellulose was further characterized by Cross and Bevan. They removed the related plant materials that occur in combination with cellulose by dissolving them in a concentrated sodium hydroxide solution. They designated the undissolved residue as a-cellulose. The soluble materials (designated as b-cellulose and ¡-cellulose) were later shown not to be celluloses, but rather, relatively simple sugars and other carbohydrates. The a-cellulose of Cross and Bevan is what is usually meant when the term "cellulose" is used now.

As a carbohydrate, the chemistry of cellulose is primarily the chemistry of alcohols; and it forms many of the common derivatives of alcohols, such as esters, ethers, etc. These derivatives form the basis for much of the industrial technology of cellulose in use today. Cellulose derivatives are used commercially in two ways, as transient intermediates or as permanent products.

Because of the strong hydrogen bonds that occur between cellulose chains, cellulose does not melt or dissolve in common solvents. Thus, it is difficult to convert the short fibers from wood pulp into the continuous filaments needed for artificial silk, an early goal of cellulose chemistry. Several different cellulose derivatives were examined as early routes to artificial silk, but only two, the acetate and xanthate esters, are of commercial importance for fibers today.

Cellulose is one of many polymers found in nature. Wood, paper, and cotton all contain cellulose. Cellulose is an excellent fiber. Wood, cotton, and hemp rope are all made of fibrous cellulose. Cellulose is made of repeat units of the monomer glucose. This is the same glucose which your body metabolizes in order to live, but you can't digest it in the form of cellulose. Because cellulose is built out of a sugar monomer, it is called a polysaccharide. Cellulose has an important place in the story of polymers because it was used to make some of the first synthetic polymers, like cellulose nitrate, cellulose acetate, and rayon.

Another cellulose derivative is hydroxyethylcellulose. It differs from plain ol' regular cellulose in that some or all of the hydroxyl groups of the glucose repeat unit have been replaced with hydroxyethyl ether groups. These hydroxyethyl groups get in the way when the polymer tries to crystallize. Because it can't crystallize, hydroxyethylcellulose is soluble in water. In addition to being a great laxative, it's used to thicken shampoos as well. It also makes the soap in the shampoo less foamy, and it helps the shampoo clean better by forming colloids around dirt particles.

Cellulose has many uses as an anticake agent, emulsifier, stabilizer, dispersing agent, thickener, and gelling agent but these are generally subsidiary to its most important use of holding on to water. Dry amorphous cellulose absorbs water becoming soft and flexible. Some of this water is non-freezing but most is simply trapped. Less water is bound by direct hydrogen bonding if the cellulose has high crystallinity but some fibrous cellulose products can hold on to considerable water in pores and its typically straw-like cavities; water holding ability correlating well with the amorphous (surface area effect) and void fraction (i.e. the porosity). As such water is supercoolable, this effect may protect against ice damage. Cellulose can give improved volume and texture, particularly as a fat replacer in sauces and dressings, but its insolubility means that all products will be cloudy.

Swelled bacterial cellulose (ex. Acetobacter xylinum) exhibits pseudoplastic viscosity like xanthan gels but this viscosity is not lost at high temperatures and low shear rates as the cellulose can retain its structure. Where individual cellulose strands are surrounded by water they are flexible and do not present contiguous hydrophobic surfaces.