Rayon, artificial textile material composed of regenerated and purified cellulose derived from plant sources. Developed in the late 19th century as a substitute for silk, rayon was the first man-made fibre. Rayon has many properties similar to cotton and can also be made to resemble silk. Readily penetrated by water, the fibre swells and loses strength when wet. It can be washed in mild alkaline solutions but loses strength if subjected to harsh alkalies. Common dry-cleaning solvents are not harmful. In apparel, rayon is used alone or in blends with other fibres in applications where cotton is normally used. High-strength rayon, produced by drawing (stretching) the filaments during manufacture to induce crystallization of the cellulose polymers, is made into tire cord for use in automobile tires. Rayon is also blended with wood pulp in papermaking.