What is Cellulose

Cellulose is the most abundant biopolymer and is present in wide variety of living species that use cellulose as a reinforcement material (trees, plants, tunicates-a group of abundant saclike filter feeding organisms found in the oceans). Cellulose is a linear chain of glucose molecules ((C6H10O5)n; n=10,000 to 15,000) linked together through an acetal oxygen covalently bonding C1 of one glucose ring and C4 of the adjoining ring. Multiple cellulose chains hydrogen bond to each other forming elementary fibrils, which collect into microfibrils that are 5-50 nm in diameter and several microns in length and have regions that are disordered (amorphous-like) and highly ordered (crystalline). These cellulose fibrils are the main reinforcement phase for the subsequent cellular structured plant tissues and cellulose nanoparticles can be extracted from plant cell walls by chemical-mechanical processes.

Cellulose particles can be considered a "green" material for several reasons. Cellulose is a polysaccharide (or carbohydrate) and has minimal environmental, health and safety risks. This is demonstrated by the various forms of cellulose that have been approved by the Food and Drug Administration for use in many consumer products in the food and medical industries, such as, but not limited to, cellophane, artificial tears, food additives (thickener, emulsion stabilizer, fiber), chronic wound treatment (scaffolding structure for tissue engineering, artificial blood vessels, cartilage, etc), and filler material within drug tablets. Additionally, the sources of CNCs are sustainable, biodegradable, carbon neutral, and have low environmental, health and safety risks. Moreover, CNCs can be processed at industrial scale quantities and at low costs (e.g. wood CNCs are a byproduct of the paper industry, and CNCs are a potential byproduct of any cellulose-to-biofuels program).


Cellulose fig. 1
(a)

Cellulose fig. 2
(b)

Cellulose fig. 3
(c)

Schematics of a) single cellulose chain, b) cellulose microfibril showing ordered (crystalline) and disordered (amourphous) regions, and c) cellulose nanocrosyals after acid hydrolysis dissolved the disordered regions.