A synthetic thermoplastic material, nylon was first introduced commercially by E.I. du Pont de Nemours and Company in the form of toothbrush bristles in 1938. The process of condensation polymerization, by which nylon and the synthetic rubber neoprene are made, was discovered by Wallace Carothers, a chemist working for the du Pont company in the 1930s. The name "nylon" itself was originally a trademark of the du Pont company, but the material is now produced in many different forms, all of which belong to the chemical group known as polyamides. Although these nylons have different characteristics and can be used in different ways, they all share the same basic qualities. In general, nylon is useful because it is a light, strong, hard-wearing material that is resistant to corrosive chemicals and can be easily molded when heated and colored with pigments. Besides these qualities, nylon is also remarkably cheap...