What Is Cotton?

Cotton is a natural textile fiber harvested from the seed hairs of plants in the genus Gossypium, primarily Gossypium hirsutum, which accounts for the large majority of global commercial production. The fiber is composed of approximately 98 percent cellulose, a linear polysaccharide whose chains are held together by hydrogen bonds and organized into crystalline and amorphous regions within each fiber cell. This molecular architecture gives cotton its characteristic combination of tensile strength, absorbency, and softness, properties that have made it the most widely cultivated natural textile fiber in the world.

Each cotton fiber is a single elongated plant cell that develops from the seed coat after fertilization. Mature fibers range from 10 to 65 millimeters in length depending on variety, and their cross-sectional shape, a flattened, ribbon-like structure with a hollow central lumen, governs spinning performance and dye uptake. Fiber fineness is measured in micronaire units, which combine fiber maturity and linear density; staple length and micronaire together determine the grade and price of raw cotton on commodity markets.

Fiber Structure and Properties

The cotton fiber develops in four distinct stages: initiation, elongation, secondary wall thickening, and maturation. During elongation, which produces most of the fiber length, the cell wall is composed of pectin, xyloglucan, and loosely organized cellulose fibrils. Secondary wall thickening then deposits nearly pure cellulose in concentric layers wound at a characteristic fibril angle to the fiber axis. This fibril angle influences tensile strength and stiffness; varieties bred for strength tend to have lower fibril angles that align the cellulose chains more closely with the load axis. Research published in PMC on cotton fiber as a model for cell wall and cellulose research demonstrated that microtubule orientation controls fibril angle rather than cellulose synthesis rate, a finding with implications for fiber engineering. Notably, cotton fiber strength increases by roughly 20 percent when wet, because moisture reinforces intermolecular hydrogen bonding within the cellulose crystalline domains.

Textile Processing and Weaving

Raw cotton undergoes several processing steps before becoming yarn. Ginning removes seeds and debris from the harvested fiber bolls. Carding combs the fibers into parallel alignment and removes short fibers and remaining plant matter; combing applies a finer version of this step to produce higher-quality combed cotton with greater uniformity. Drawn slivers are then drafted and twisted into yarn on ring, open-end, or air-jet spinning frames, each producing yarn with different structural characteristics. Woven cotton fabrics are produced on shuttle or shuttleless looms by interlacing warp and weft yarns in plain, twill, or satin structures that determine the fabric's hand, appearance, and mechanical properties. The ScienceDirect overview of cotton fiber properties in materials science covers the relationship between fiber quality parameters and downstream fabric performance across these processing routes.

Knitting and nonwoven fabrication provide alternative routes. Knit cotton, formed by interlocking loops, offers higher stretch and is dominant in garment applications. Nonwoven cotton fabrics, formed by hydroentangling or thermal bonding, are used in medical and hygiene products where controlled absorbency and disposability matter. The review of natural fiber advances for textile and non-textile applications at IntechOpen documents how cotton's biocompatibility supports its use in wound dressings, surgical gauze, and other medical textiles.

Applications

Cotton has applications across a wide range of industrial and consumer sectors, including:

• Apparel and fashion, where its breathability and dye affinity make it the dominant material for casual and workwear
• Home textiles, including bed linens, towels, and upholstery
• Medical and hygiene products, including bandages, surgical swabs, and absorbent pads
• Industrial textiles, including canvas, tarpaulins, and filtration fabrics
• Composite reinforcement in natural fiber polymer composites for automotive and construction applications