In 1504, on the last of his four voyages to the new world, Columbus visited Central America and Mexico; A region now referred to as Mesoamerica. During his visit, he observed that the native people tapped latex from local trees and used it to make an interesting elastic compound. Columbus, and later the Spanish Conquistadors, brought samples of these trees back to Europe and they were distributed to naturalists and others. In 1770, the English chemist Joseph Priestley performed much research on this odd elastic compound and it was he that came up with the term “rubber.” His coining of the term came directly from the fact that early rubber in Europe was used in erasers which were used “to rub.”
It’s a polymer
Like plastic, rubber is a polymer which is a chemical chain of repeating units called monomers. In rubber, the monomer is a carbon compound called Isoprene.
The latex fluid that seeps from rubber trees is made up of isoprene molecules. As the latex dries, the isoprene molecules bunch up and one isoprene molecule attacks a carbon-carbon double bond of a neighboring molecule. When this happens, a new bond is arranged between isoprene molecules and a polymer begins to grow.
Vulcanization is the chemical process that converts natural rubber into a more durable form. Developed by Charles Goodyear in 1839, vulcanization is accomplished by adding sulfur and other additives to the rubber latex compound. These additives modify the compound by forming additional cross-links between the polymer chains. This yields a rubber compound that is less sticky and has superior mechanical properties. Vulcanized rubber was soon being used to make products such as shoe soles, hoses, conveyor belts and much more.
The rubber industry really started booming with the invention of the automobile. Originally the horseless carriages had wooden wheels but these were far too primitive for motorised vehicles and they quickly evolved into metal disc wheels. Helping us with this article, the folks at Kindle Autoplaza of Cape May Court House, a local Chrysler, Dodge, Jeep, Ram, Ford, Lincoln dealer in Cape May Court House, NJ told us that the first metal wheels had just a ring of hard rubber around it’s circumference. It wasn’t until the 1900s when the pneumatic tire was developed, then the rubber trade exploded.
It was only a matter of time before scientists started work on artificial rubber. As early as 1860, chemists had heated rubber to break it apart and found that it produced isoprene, oil and tar. All they had to do was make isoprene from oil and then combine it artificially to make rubber. Early experiments were promising but the actual process for making high-quality synthetic rubber wasn’t worked out until early in the 1900s.
It’s a big industry
How much rubber is bouncing around out there? Ha, ha. According to the International Rubber Study Group, over 10 million tons of natural rubber was produced in 2015 with most of the raw material coming from Asia. At approximately $2,330 per ton, the natural rubber market involved about $23 billion in 2015.