A giant jumbo jet approaches an airport. A lot depends on the tires for a successful landing. They have to withstand tremendous impact and friction when the airplane, with its enormous weight, falls and comes to a stop. The only natural substance capable of withstanding this shock is rubber.
Where does rubber come from? Many tropical and subtropical trees produce a milky liquid, or latex, which contains rubber. The best commercial source of natural rubber is a beautiful upright tree called Hevea brasiliensis, which is native to the Amazon rainforest of Brazil. It grows spontaneously to a height of 20 to 30 meters. These trees grown in plantations reach a height of 18 meters. Regarding the origin of rubber containing latex, the Encyclopædia Britannica states:
“The trunk of the tree can be divided into an inner part of wood and an outer part of bark. At the intersection of the bark and the wood is a layer of cells the thickness of a sheet of paper called a cambium, which appears as a slimy layer when the bark is pulled from the tree. This layer is the place of growth, on the one hand it adds new cells to the wood and on the other hand new cells to the bark. The latex tubes are located next to the replacement and in the soft part of the cortex. On the outside, the softshell is a tough part where there are relatively few latex tubes. The whole is protected by an outer layer of cork. The diameter of the latex tubes is assumed to be 0.0038 cm.”
Rubber molecules consist of five carbon atoms and eight hydrogen atoms. Many of these linked molecules form huge, long-chain molecules called polymers many parts).Concerning the gum, “Researchers believe that the rubbery composition of the gum may explain its ability to stretch.They believe that long chains of rubber molecules can connect and twist, like a kind of spiral spring. When the rubber is stretched, the coils separate. After their release, they will return home. "
Touch the jungle trees
Over 150,000 Brazilian parents make a living from harvesting wild natural rubber in inhospitable forests near the Amazon.There daily routine begins at dawn near the town of Rio Branco, in the state of Acre, about 1,100 kilometers south of the equator, in the jungle. After a frugal breakfast,they step outside and light up the dense jungle with a small headlamp. Also, carry a shotgun to avoid the dangers posed by wild animals or snakes.
When the first tree is reached,cleaning the trunk is first done.Then a special knife is used to lighten the crust and flip the cut from left to right and place a metal bowl in each cup. This is to capture the milky sap that seeps between the outer layer of the plug and is exchanged over the next three to four hours. If a tree is above average in terms of production,four cups are put up at the same height, spaced about 4 inches apart.
At noon,a break is taken for a light meal. But soon after, the collection of the latex begins.This produces about 10 kg of raw rubber.
The following procedure is carried out on a thatched roof without a window, but with an opening in the roof. A slow-burning fire burns in the center of the hut with a fork-shaped branch on either side.A stick is dipped in the latex several times then placed it on the forks. When you turn the rod on the fire, more latex will be poured onto the rod. The heat evaporates the water from the latex and the rubber thickens. The process of adding the latex continues and gradually takes the solid form of a dark rubber ball around the bar. This continues until the ball weighs 20 kg or more.
Regularly deliver heavy rubber bales to an agent where they will be weighed, sorted and paid for. Then they are sent to industrial centers.
Small beginning
The rubber tree was known to the Indians of tropical America. They called it chewing gum,to mean a "crying tree". They used latex to create shoes, cloth lining, pear-shaped bottles, animal dolls and balls for the children to play with.
What is the origin of rubber? Its origins go back to the 18th century, when the British chemist Joseph Priestly used scrap metal to erase pencil marks. Which name is more appropriate than "eraser", because the substance effectively erases writing? This term remained.
In the 19th century, rubber looked promising for trade. At the time, a Scottish chemist, Charles Macintosh, applied rubber to a fabric to make it waterproof. This is where our raincoats, known to some as the "Mackintosh", were born.
However, the use of rubber was very limited at that time. This was mainly due to the fact that pure rubber is affected by heat and cold. In hot climates it becomes sticky, smelly and dies easily, while in cold climates it hardens and becomes brittle. But in 1839, an American, Charles Goodyear, found a way to deal with these weaknesses.
During experiments, Goodyear came up with the idea of adding sulfur and turning it into raw rubber and heating the compound to high temperatures. The resulting rubber had no defects other than pure rubber and also had greater elasticity and resistance to friction. The process became known as vulcanization in honor of the Roman fire god Vulcan.
This invention marked a turning point in the manufacture of rubber goods. Another advance was the invention of rubber tires, including tires, for cars and other vehicles. As a result, demand for rubber has exploded.
Rubber plantations
At the height of the "rubber speed", traders invaded the Amazon and the rubber barons made their fortune. Prices rose to one dollar per pound (454 grams). Manufacturers began looking for cheaper rubber sources.
To date, Brazil is the only supplier of raw rubber. Would it be possible to make rubber trees bloom elsewhere? In 1876, Henry Wickham managed to bring about 70,000 Brazilian rubber tree seeds to England. These were planted in greenhouses at the Royal Botanic Gardens in Kew, London.The plants were transported to Ceylon and Malaysia for replanting. With what result?
Today, about 85% of the world's natural rubber supply comes from Southeast Asia, with Malaysia as the largest producing region. There are also rubber plantations in Africa, mainly in Liberia and Nigeria.
Synthetic rubber
The great demand for rubber during two world wars led to the invention of synthetic rubber from sources such as coal and oil. The term "synthetic" means "assembled". Among these artificial products, some are better than natural rubber for certain uses.
Synthetic rubber includes neoprene, which is particularly resistant to oil, petrol, sunlight and ozone. "Arctic" rubber resists curing and brittleness at low temperatures. Firestone "Coral" is said to be a virtual copy of natural rubber.
