In 1891 Hilaire Chardonnet developed rayon, the first man made fiber from natural cellulose. In 1938 the first truly synthetic fiber, nylon was developed by creating fiber like macromolecules. Adipic acid and hexanethaline diamine combined with water to create nylon salt. The water is evaporated until the long molecules hook up into long fibers to create nylon yarn. Fabrics are tested for crease resistance, stiffness, resilience, and wear. Sometimes they are combined with natural fibers to form stronger blends.