The clothes that you put on every day are made from a variety of materials. These materials are either natural, derived from substances occurring in nature, or synthetic, composed from substances that are man-made. Two materials that many clothing manufacturers use are rayon and acrylic thread. Both of these materials are considered synthetic, but beyond that, the two are quite different.

The first difference between acrylic thread and rayon concerns the categorization of the two materials. While acrylic thread is entirely synthetic, rayon is not. It is considered semi-synthetic because it is not entirely natural and not entirely man-made. Rayon is composed of chemically-treated cellulose (plant) fibers.

Acrylic thread and rayon are produced through slightly different manufacturing processes. Manufacturing acrylic thread involves creating a polymer out of polyacrylonitrile by immersing it in a chemical solvent, such as N,N-dimethylformamide. Rayon is produced by immersing cellulose in sodium hydroxide, then carbon disulfide, and lastly in sulfuric acid. Both materials are eventually extruded through a spinneret (a device with tiny holes used for making thread) which forms the fibers. The fibers are then washed, stretched, dried and cut.

Acrylic fabric is a good wool substitute for those who are allergic to natural wool, though the fabric itself can cause skin irritation in eczema sufferers. Rayon is a suitable substitute for silk and is even known by the trade name, art silk. Acrylic fabric is very soft, plush and thick, whereas rayon is a very thin fabric. Rayon, because it is so thin, is generally not as strong and resistant to tears as acrylic thread, but there are types of rayon, such as High wet modulus rayon (HWM), that are incredibly strong, especially when wet.

While rayon is still manufactured in some textile plants in the United States, acrylic thread is not produced in the United States; only some of its precursor components are still produced in the U.S. Rayon is also highly biodegradable, whereas acrylic fabric is not biodegradable at all. Acrylic fabrics tend to become fuzzy and pill (form tight balls on the surface of the fabric) over time; rayon does not pill or become fuzzy. Rayon is highly flammable, whereas acrylic thread is flame-resistant and only melts under intense heat.