Textile Fiber Microscopy

4Regenerated Cellulosic and Protein Fibers

4.1 Regenerated Cellulosic Fibers

Rayon is a manufactured regenerated cellulosic fiber. It differs from other manufactured or synthetic fibers due to its cellulosic content. The production of manufactured fibers was motivated by the desire to make a fiber closely resembling silk. Unsuccessful attempts to imitate silk date back to 1664. It was only in the late nineteenth century that these attempts were successful.

Rayon, the first manufactured fiber, was invented by an English scientist, Charles Frederick Cross, and his colleagues. They invented the viscose process, used to manufacture viscose rayon, in 1891. Most rayons today, including bamboo rayon, are manufactured using this viscose process. Rayons are made out of cellulose, a natural compound, taken from a variety of plant sources; one example is wood pulp harvested from eucalyptus trees, which is later mixed with other chemicals. Under the microscope, we cannot see cellulosic content because in the manufacturing process, the natural cellulose is converted to a soluble cellulosic derivative. The resulting cellulosic solution is then extruded through a spinneret, a device resembling a showerhead, into a chemical bath where it hardens into fibers. This is called wet‐spinning coagulation, which is used in manufacturing fibers. Thus, the shape of rayon fibers or any other manufactured fibers, examined microscopically, is a result of the spinneret's shape. The spinnerets are engineered ...