Synthetic Polymer Fibers
Synthetic fibers are generally semicrystalline polymers that are spun into filaments. The fibers are uniaxially oriented during the melt, dry, or wet spinning process, which give the fibers high tenacity and strength. The synthetic fibers are then converted to yarn by twisting several continuous fibers together to a uniform yarn with all filaments more or less alligned parallel to the yarn axis.
Commercially produced fibers can be classified as cellulosic and noncellulosic fibers.
Cellulosics are derived from naturally occuring cellulose through chemical reactions
and processing. The most important types of cellulose
based fibers are cellulose acetate (Acetate), regenerated cellulose (Viscose Rayon), Cuprammonium Rayon (Bemberg), and saponified acetate (Rayon).
Cellulosic fibers represent only a small fraction of the fiber market. Many other synthetic fibers are in use today. Common non-cellulosic fibers include Nylon (1931), Olefin (1949), Acrylic (1950), Polyester (1953) and Spandex (1959).
Synthetic fibers are more durable than most natural fibers. In addition, the properties of synthetic fibers and fabrics can be easily taylored to the application by varying the chemical composition and the process conditions. For example, they can be flexible and elastic or stiff and strong or they can have high or low water absorbancy. Compared to natural fibers, synthetic fibers are usually more water, stain, heat and chemical resistant. In general, natural fibers are more sensitive than synthetic fibers because they are biodegradable, can be attacked by various bacterias and fungi (mildew), and break and wear down over time, whereas most synthetic fibers are non-biodegradable.
However, synthetic fibers have also some disadvantages; most of these are related to their low melting point and/or their chemical composition. For example, certain synthetic fibers are prone to heat damage by hot washing. They also have a stronger tendency to electrostatic charging when rubbing against other materials, and they are not always skin friendly, and, in some cases, can cause allergic reactions. Some commercial fibers, like polyester and nylon, do not absorb sweat as much and quickly as natural fibers. For these reasons, synthetic fibers are sometimes blended with natural fibers, like cotton and wool.