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Forty years ago, anything made of plastic was considered "cheap." That’s certainly not true today when plastics are used in thousands of products ranging from computers, automobile parts and important medical equipment to toys, cookware, sports equipment, and even clothes. And the plastics industry continues to grow rapidly. Just where do plastics come from? What are plastics? It may surprise students to learn that gutta-percha, shellac, and the horns of animals—all naturally occurring substances—were used as plastic material before the first synthetic plastics were produced. Gutta-percha is derived from the sap of certain trees, and shellac is made from the secretions of a tiny scale insect. Before horn can be used, however, it must be "plasticized," or softened, by being boiled in water or soaked in an alkaline solution. The first synthetic plastic was made from the plant material cellulose. In 1869, John Wesley Hyatt, an American printer and inventor, found that cellulose nitrate could be used as an inexpensive substitute for ivory. The mixture could be plasticized with the addition of camphor. Celluloid, as this new material was called, became the only plastic of commercial importance for 30 years. It was used for eyeglass frames, combs, billiard balls, shirt collars, buttons, dentures, and photographic film. In 1951, two young research chemists for Phillips Petroleum Company (now ConocoPhillips) in Bartlesville, Okla., made discoveries that revolutionized the plastics world. Today, the plastics they discovered—polypropylene and polyethylene—are used to produce the vast majority of the thousands of plastics products all over the world. (Read more about their discoveries in "Serendipity, Science & Discoveries" in this publication.) The source for today’s wide
variety of plastics? Petroleum.
Last Updated: 02/16/03 |
