Finding the Right Stuff

A cook without a recipe book is forced to experiment—a dash of salt here, a few onions there, vary the temperature, and then taste the result. In 

Plastics are one example. Scientists use the term plastic to refer to polymers, which are materials composed of a chain of bonded molecules. For instance, most credit cards are made from a plastic known as polyvinyl chloride (PVC), which consists of linked molecules of vinyl chloride. (Old vinyl record albums were often made from the same material.) The first plastic made entirely in the laboratory (as opposed to natural products) was Bakelite, concocted aroimd 1908 by the Belgian-American chemist Leo Baekeland (1863-1944). 

One of the primary motivations for developing plastic was the burgeoning electronics industry of the late 19th century. Electrical engineers needed a flexible material that was not an electrical conductor, with which they could protect and insulate electrical wires and circuits. Chemists had been experimenting with materials such as phenol and formaldehyde for decades before Baekeland hit upon the right combination of these substances, as well as the right temperature and pressure at which they would combine to form a useable plastic. 

Since the development of Bakelite, many other types of plastic have appeared. Plastics have a huge number of applications today, including bags and containers of all shapes and varieties. 

Materials called composites are also in widespread use. A composite consists of small fibers of one substance embedded in a matrix of another substance. The fibers reinforce the matrix, adding stiffness. One of the first composites was fiberglass, in which thin fibers of glass reinforce a plastic material. Fiberglass is strong yet light in weight. 

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