How Is Rubber Made From a Rubber Tree?
Rubber trees originally grew only in Brazil. Attempts in the late 19th century to export seedlings of the tree failed, but later attempts succeeded and today you can find commercial plantations in tropical climates all over the world: Central America, Africa and particularly Southeast Asia. The tree's scientific name, Hevea Brasiliensis, reflects its Brazilian origins; the popular name comes from 19th-century English scientist Joseph Priestley, who observed that you could "rub" away pencil marks with the tree's dried sap. Today about 70 percent of rubber is produced synthetically from petroleum.
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Commercial Rubber Plantations
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Commercial plantations rely on bud grafting, a form of cloning, to produce saplings with desirable traits. Mature rubber trees grow as high as 100 feet. The trees mature in about a decade, but tapping, the process of harvesting the latex, can begin somewhat sooner, after about five to eight years.
Latex and Sap
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Rubber, the product, originates as latex, commonly and incorrectly described as the sap of the rubber tree. The tree's sap comes from deep within the trunk and has no commercial application. Outside the tree's cambium layer, however, a layer of ducting in the bark contains latex, a gummy fluid and the source of natural rubber.
Tapping the Latex
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To tap the rubber tree you wrap a long metal ribbon around the trunk in a gradually descending spiral beginning about 40 inches from the ground. You then make a long cut about two-thirds of the way through the bark all along the edge of the ribbon. Next, you gouge out a channel along the length of the cut, then continue the gouge as a vertical channel running a couple of feet down the trunk. At the bottom of the channel you tie a cup. The latex seeps out of the gouge and follows the channel until it drops down into the cup.
Early Rubber Compounds
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Rubber had limited utility until the middle of the 19th century, when Charles Goodyear happened upon the process we know now as vulcanization. Prior to Goodyear's discovery latex grew runny in warm weather and hardened excessively in cold weather.
Goodyear Discovers a Stabilizing Process
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Historians commonly credit Goodyear with the invention of vulcanization; more accurately, he discovered it by accident when he spilled a mixture of latex, lead and sulfur on a hot stove. When he removed it he noticed that the compound had stabilized into a firm but pliable substance. All natural rubber today derives from some form of Goodyear's original vulcanizing process. The word originates from the Roman name, Vulcan, for the Greek god Hephaestus, a fire god skilled in blacksmithing.
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Comments
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God created the rubber tree.
