Substances or materials produced by chemical processes rather than occurring naturally.

Polyester is the general name for any group of widely used synthetic products. Polyesters are strong, tough materials that are manufactured in a variety of colors, shapes and sizes. The first commercial production of polyester was by the du Pont de Nemours Company. It is the most used fiber in the United States. Polyester fibers are used to make fabrics. Poly (ethylene terephthalate, or simply PET) is the most common polyester used for fiber purposes. This is the polymer used for making soft drink bottles. Recycling PET by re-melting it and extruding it as fiber saves raw material as well as energy.

Polyesters are the polymers, in the form of fibers that were used back in the seventies to make all that wonderful disco clothing. But since then, the nations of the world have striven to develop more tasteful uses for polyesters, like those nifty shatterproof plastic bottles that hold your favorite refreshing beverages. Polyesters can be both plastics and fibers.

Nylon is made by forcing molten nylon through very small holes in a device called a spinneret. The streams of nylon harden into filament once they come in contact with air. They are then wound onto bobbins. These fibers are drawn (stretched) after they cool.
Drawing involves unwinding the yarn or filaments and then winding it around another spool. Drawing makes the molecules in each filament fall into parallel lines. This gives the nylon fiber strength and elasticity.

Nylon was introduced in the 1930s. It was another early substitute for silk and soon quickly became the fiber of choice for women's stockings. The first commercial production of nylon in the United States was in 1939 by the E.I. du Pont de Nemours and Company. Wallace H. Carothers, a chemist of the Dupont Company played the leader in this development of nylon. This man-made fiber is the second most used fiber in the United States.