In this century, nothing can't turn us from using plastics. Before the invention of plastic, the only substances that could be molded were clays (pottery) and glass. Hardened clay and glass were used for storage, but they were heavy and brittle. Plastics first hit the scene in the second half of the 19th century and eventually became a top manufacturing material.
Plastics are made from oil. Oil is a carbon-rich raw material, and plastics are large carbon-containing compounds. They're large molecules called polymers, which are composed of repeating units of shorter carbon-containing compounds called monomers. Chemists combine various types of monomers in many different arrangements to make an almost infinite variety of plastics with different chemical properties. Most plastic is chemically inert and will not react chemically with other substances -- you can store alcohol, soap, water, acid or gasoline in a plastic container without dissolving the container itself. Plastic can be molded into an almost infinite variety of shapes, so you can find it in toys, cups, bottles, utensils, wiring, cars, even in bubble gum.
The inventions of plastics began in 1839, when Charles Goodyear accidentally discovered a process in which sulfur reacted with crude rubber when heated and then cooled. The rubber became resilient upon cooling -- it could stretch, but it snapped back to its original shape. It also retained its resilience when heated. We now know that the sulfur forms chemical bonds between adjacent rubber polymer strands. The bonds cross-link the polymer strands, allowing them to "snap back" when stretched. Charles Goodyear had discovered the process now known as vulcanization, which made rubber more durable.
In 1846, Charles Schonbein, a Swiss chemist, accidentally discovered another polymer when he spilled a nitric acid-sulfuric acid mixture on some cotton. A chemical reaction occurred in which the hydroxyl groups of the cellulose fibers in the cotton were converted to nitrate groups catalyzed by the sulfur. The resultant polymer, nitrocellulose, could burst into a smokeless flame and was used by the military in place of gunpowder.
In 1870, chemist John Hyatt reacted nitrocellulose with camphor to make celluloid, a plastic polymer that was used in photographic film, billiard balls, dental plates and Ping-Pong balls.
In 1909, a chemist named Leo Baekeland synthesized Bakelite, the first truly synthetic polymer, from a mixture of phenol and formaldehyde. The condensation reaction between these monomers allows the formaldehyde to bind the phenol rings into rigid three-dimensional polymers. So, Bakelite can be molded when hot and solidified into a hard plastic that can be used for handles, phones, auto parts, furniture and even jewelry. Bakelite is hard, resistant to heat and electricity, and can't be easily melted or scorched once cooled. The invention of Bakelite led to a whole class of plastics with similar properties, known as phenolic resins.
Today, because of the environmentally unfriendly and unsustainable nature of plastic, some manufacturers are looking to better sources of raw materials for plastic production. Nonpetroleum plastics will likely become more and more common as researchers continue to find ways of creating polymers from such organic sources as corn, orange peels, bamboo, papermaking byproducts and hemp.
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