Plastics are a type of polymer characterized by the fact that they can be molded with heat. Thermoset polymers are extremely rigid and once molded and hardened cannot be remelted. Thermoplastic materials are softer, more flexible and may be remelted. They are also recyclable.

The first plastics were often based on cellulose. One of the first plastics was developed to take the place of a material in short supply. In 1836, the Phelan and Collender company, makers of ivory billiard balls, sponsored a contest with a $10,000 prize for the inventor of synthetic ivory. John Wesley Hyatt and his brother set out to win the prize. Building on the research of Parkes and Schonbein they formed celluloid out of colloidian in 1875. Although they did not win the prize, the Hyatt brothers founded a company and successfully marketed celluloid. Alexander Parkes (1813-1890) patented his cellulose nitrate material called Parkesine in 1855. The...