Manufacture of synthetic rubber
Successful industrial synthesis of rubber is the most significant achievement of the science and technology in the XX century. The industry needs obviously surpassed the natural potential of the rubber plants. For the first time in the world the rubber synthesis in a large scale was carried out in 1932 in the USSR by S.V.Lebedev. In 1938 the manufacture of synthetic rubber was organized in Germany, in 1942 - in the USA. By 1972 synthetic rubber had been being produced in more than 20 countries.
Creating synthetic rubber S.V.Lebedev followed the way of nature. So long as natural rubber is a polymer of diene hydrocarbon, S.V.Lebedev used diene hydrocarbon as well, but more simple and accessible that is butadiene. As a raw material for production of butadiene was ethyl alcohol. Produced synthetic rubber was similar to natural one and even excelled it in some ways. But natural rubber was more elastic than synthetic one, meanwhile the elasticity is the most important property of the automobile and aviation trunks felt repeated deformation when they move.
The further researches showed that natural rubber has the stereoregular structure, the groups -CH2- in the macromolecule of rubber are located on the one side of a double connection in each part, not randomly, i.e. are in the cis-position. Such position of the groups -CH2- promotes the natural twist of the macromolecule into a ball that imparts high elasticity to rubber. In case of the trance-structure of the macromolecule the parts become more extended and less elastic. The stereoregular structure was impossible, but nevertheless the problem managed to be solved owing to the catalyst (metal sodium) which provides the stereoregular structure in a growing polymeric chain. As a result synthetic rubber looks like natural one; it possesses good water- and gas tightness. For increasing the durability and elasticity it was subjected to the vulcanization as well as natural rubber.
Wide use of butadiene rubber for the manufacture of various rubber products caused the serious changes of a raw-material base. Before as a raw material for butadiene they used ethanol which was produced from grain and potatoes. The economy interests demanded more accessible raw material, therefore nowadays for the rubber synthesis the hydrocarbons containing in oil gases and in oil refining products are used.
Just as natural rubber is obtained from latex, synthetic rubber is obtained from synthetic latex. It is produced from two basic substances: butadiene-1,3 and sterol. Butadiene-1,3 is the gas obtained from oil, and sterol - the liquid extracted from oil and coal. Butadiene-1,3 and sterol are placed in the great containers with a soap solution which facilitates the formation of the rubber parts. Catalysts are added. After that the liquid is mixed up and gains the dairy color. This is synthetic latex which is externally very similar to natural one. When synthetic latex gets the necessary standard, the stopping reaction inhibitors are added. Then latex is placed into other container with an acid and a hydrochloric solution where latex is curtailed. The curtailed rubber slices look like grey grains which washed to remove unnecessary chemical substances. Synthetic rubber is dried and pressed in granules.
There are different kinds of synthetic rubber. They are produced with addition of various substances.
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