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"This particular project is very exciting because the Mesoamerican rubber ball game was such a fundamental ritual and political event in these societies, and the ball game could not have developed without inventing the technology to process rubber." Dr. Dorothy Hosler.
Rubber. Our cars would certainly give a worse ride without the stuff. But what is rubber, exactly? And where does it come from?
ANCIENT RUBBER
Until recently modern thinkers believed rubber originated in 19th century Europe. According to a Tech Talk article published by Massachusetts Institute of Technology on Wednesday, July 14, 1999, Professor Dorothy Hosler, Assistant Professor Sandra Burkett and an undergraduate named Michael Tarkanian learned that the Mayan people in ancient Mesoamerica made and used rubber as long ago as 1600 BCE.
The ancient Mayan people used latex to make rubber balls, hollow human figures, and as bindings used to secure axe heads to their handles and other functions. Latex is the sap of various plants, most notably the rubber tree. When it is exposed to the air it hardens into a springy mass. The Mayans learned to mix the rubber sap with the juice from morning glory vines so that it became more durable and elastic, and didn't get quite as brittle. Both the rubber tree and the morning glory were important plants to the Mayan people- the latter being a hallucinogen as well as a healing herb. They two plants tended to grow close together. Combining their juices, a black substance about the texture of a gum-type pencil eraser was formed.
The rubber balls were about the size of a beach ball and weighed over 15 pounds (7 kilograms). These were used in an important ritual game called Tlachtlic. The game was a cross between football and basketball, but had religious significance as recorded in the Popul Vuh, a Mayan religious document. Spanish invaders in the sixteenth century reported that the game also involved gambling for various possessions including land and slaves. It is believed that the game ended in a human sacrifice at least some of the time. Versions of the game were played in the middle American region ranging from southern Arizona to northern South America. Native peoples in the region still make rubber in the same way.
VULCANIZED RUBBER
In 1736 several rolled sheets of rubber were sent to France where it fascinated those who saw it. In 1791, an Englishman named Samuel Peal discovered a means of waterproofing cloth by mixing rubber with turpentine. English inventor and scientist, Joseph Priestly, got his hands on some rubber and realized it could be used to erase pencil marks on sheets of paper.
Charles Goodyear, an American whose name graces the tires under millions of automobiles, is credited with the modern form of rubber. Before 1839, rubber was subject to the conditions of the weather. If the weather was hot and sticky, so was the rubber. In cold weather it became brittle and hard. Goodyear's recipe, a process known as vulcanization, was discovered when a mixture of rubber, lead and sulfur were accidentally dropped onto a hot stove. The result was a substance that wasn't affected by weather, and which would snap back to its original form if stretched. The process was refined and the uses for rubber materials increased as well. This new rubber was resistant to water and chemical interactions and did not conduct electricity, so it was suited for a variety of products. The process of making the rubber product improved as time went by, and now various chemicals are added before the mix is poured into molds, heated and cured under pressure.
An Englishman named Sir Henry Wickham collected about seventy thousand rubber tree seeds in Brazil in 1876 and took them to the East Indies where he started rubber plantations. In 1877 an American named Chapman Mitchell learned to recycle used rubber into new products.
MODERN RUBBER
Today about three quarters of the rubber in production is a synthetic product made from crude oil. World War II cut the United States off from rubber supplies worldwide, and they stepped up production of synthetic rubber for use in the war effort. There are about 20 grades of synthetic rubber and the intended end use determines selection. In general, to make synthetic rubber, byproducts of petroleum refining called butadiene and styrene are combined in a reactor containing soap suds. A milky looking liquid latex results. The latex is coagulated from the liquid and results in rubber "crumbs" that are purchased by manufacturersand melted into numerous products.
There is only one kind of natural rubber. Because the rubber plant only thrives in hot, damp regions near the equator, so 90% of true rubber production today occurs in the Southeast Asian countries of Malaysia and Thailand and in Indonesia. Indonesia's production has dropped in recent years and new plantations were started in Africa to take up the slack.
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