PLASTICS LIFECYCLE | CHAPTER 1 | WHAT is PLASTIC?
A plastic is a type of synthetic or man-made polymer; similar in many ways to natural resins found in trees and other plants. Webster’s Dictionary defines polymers as: any of various complex organic compounds produced by polymerization, capable of being moulded, extruded, cast into various shapes and films, or drawn into filaments and then used as textile fibers.
A Little History
The history of manufactured plastics goes back more than 100 years. Their usage over the past century has enabled society to make huge technological advances. Although plastics are thought of as a modern invention, there have always been “natural polymers” such as amber, tortoise shells and animal horns. These materials behaved very much like today’s manufactured plastics and were often used similarly to the way manufactured plastics are currently applied. For example, before the sixteenth century, animal horns, which become transparent and pale yellow when heated, were sometimes used to replace glass.
Alexander Parkes unveiled the first man-made plastic at the 1862 Great International Exhibition in London. This material—which was dubbed Parkesine, now called celluloid—was an organic material derived from cellulose that once heated could be moulded but retained its shape when cooled. Parkes claimed that this new material could do anything that rubber was capable of, yet at a lower price. He had discovered a material that could be transparent as well as carved into thousands of different shapes.
In 1907, chemist Leo Hendrik Baekland, while striving to produce a synthetic varnish, stumbled upon the formula for a new synthetic polymer originating from coal tar. He subsequently named the new substance “Bakelite.” Bakelite, once formed, could not be melted. Because of its properties as an electrical insulator, Bakelite was used in the production of high-tech objects including cameras and telephones. It was also used in the production of ashtrays and as a substitute for jade, marble and amber. By 1909, Baekland had coined “plastics” as the term to describe this completely new category of materials.
The first patent for polyvinyl chloride (PVC), a substance now used widely in vinyl siding and water pipes, was registered in 1914. Cellophane was also discovered during this period.
Plastics did not really take off until after the First World War with the use of petroleum, a substance easier to process than coal into raw materials. Plastics served as substitutes for wood, glass and metal during the hardship times of World Wars I & II. After World War II, newer plastics, such as polyurethane, polyester, silicones, polypropylene, and polycarbonate joined polymethyl methacrylate, polystyrene and PVC in widespread applications. Many more would follow, and by the 1960s plastics were within everyone’s reach due to their inexpensive cost. Plastics had thus come to be considered ‘common’—a symbol of the consumer society.
Since the 1970s, we have witnessed the advent of ‘high-tech’ plastics used in demanding fields such as health and technology. New types and forms of plastics with new or improved performance characteristics continue to be developed.
From daily tasks to our most unusual needs, plastics have increasingly provided the performance characteristics that fulfil consumer needs at all levels. Plastics are used in such a wide range of applications because they are uniquely capable of offering many different properties that offer consumer benefits unsurpassed by other materials. They are also unique in that their properties may be customized for each individual end use application.
Chapter 2 next week: The fossil fuel connection