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Natural &-syn-rubber


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Natural rubber tree is cultivated in Asia and a large supplement needed for tyre industry is synthesised based on monomers derived from olefines & benzene.

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Natural &-syn-rubber

  1. 1. Natural Rubber: Natural rubber is a solid product obtained through coagulating thelatex produced by certain plants, particularly the Brazilian rubber-tree(Hevea Brasiliensis). This raw material is usually tapped from the rubbertree, which is native to Amazonia. Although there a large number of speciesthat exude secretions similar to latex when the bark is cut, only a fewproduce sufficient quantities of a quality adequate for exploitation oneconomic bases. Thanks to its multiple applications, particularly in the expandingautomobile industry, rubber produced from latex tapped from rubber-treesbecame a product in demand worldwide. Asia came to dominate global supplies of natural rubber with over90% of the output. The main competitors were Thailand, Malaysia(Indonesia), China and India. By 2001, natural rubber consumptionaccounted for some 40% of the total amount of rubber consumed worldwide. The worlds natural rubber plantations had a grip on the tire industryand during war the need for lower-cost products with steadier supplies inorder to manufacture tires was felt strongly. This triggered much interest indiscovering the chemical composition of natural rubber and its effect onproperties, in order to synthesize this product.Synthetic Rubber: This was how GR-S, Buna S, Hycar OS and SBR appeared. These arestyrene and butadiene copolymers. The launch-pad for the massivedevelopment of the synthetic rubber industry, this product could bevulcanized easily, and became the flagship of the world rubber industry,although its properties did not correspond to all the qualities of naturalrubber. But its costs and main characteristics made it into an unbeatablecompetitor. Although synthetic rubber had been known since 1875, itsproduction had been expensive and almost negligible. During World War II, a crucial historical episode altered the scenariofor this market. On December 7, 1941, the USA entered the War. Threemonths after the attack on Pearl Harbor, the Japanese invaded Malaysia andthe Dutch East Indies, desperate to take over natural rubber production fromthe allies. This gave the Axis control over 95% of world rubber supplies,plunging the USA into a crisis.Each Sherman tank contained twenty tons of steel and half a ton of rubber.Each warship contained 20,000 rubber parts. Rubber was used to coat everycentimeter of wire used in every factory, home, office and military facilitiesthroughout the USA. There was no synthetic alternative. Looking at all thepossible sources, at normal consumption levels, the nation had stocks foraround one year. And these reserves also had to supply the largest and mostcritical industry in the history of the world during a time of rapid expansion:the arms segment. Under these circumstances, an order was sent to allchemists and engineers to develop a synthetic rubber industry. In 1941, the 1
  2. 2. total output of synthetic rubber barely topped 8,000 tons, consisting largelyof products not suitable for tires. The nations survival depended on its capacity to manufacture over800,000 tons of products that had barely begun to be developed. There werefew detailed instructions on how the factories should organize themselves toproduce this vast amount. No facilities had been built, nor were there anyways of producing enough raw materials to produce rubber.A wide variety of synthetic rubbers have been developed since this productwas first discovered. As massive investments were required to develop thesedifferent varieties, the production technology was heavily concentrated inlong-established global enterprises such as DuPont, Bayer, Shell, Basf,Goodyear, Firestone, Michelin, EniChem, Dow, and Exxon.The use of rubber is widespread, as the characteristics and properties ofthese elastomers make them useful in almost all economic sectors:automobiles, footwear, civil construction, plastics, hospital materials andothers that are of crucial importance in the daily life of society. As they aremost widely used to produce tires, the SBR and BR varieties are the mostwidely consumed type of synthetic rubber. 2
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