A chemical compound formed by a reaction in which two or more molecules combine to form larger molecules with repeating structural units.
Example:
Nylon, a polymer commercially introduced in 1938, can be spun and woven into fabrics or cast as tough, elastic blocks.
There are natural polymers, such as shellac and rubber, but synthetic polymers came into being in 1870 with Celluloid, which, although a synthetic compound, is made from natural cotton and camphor. After many decades of development, the polymeric compounds now include polypropylene, used in milk crates, luggage, and hinges; polyurethane, used in paints, adhesives, molded items, rubbers, and foams; and polyvinyl chloride, used to make pipes that won't rust.