Natural Vs Synthetic Rubber
Natural rubber, coming from latex, is mainly poly-cis-isoprene containing traces of impurities. Although it exhibits many excellent properties, natural rubber is often inferior to synthetic rubbers, especially with respect to its thermal stability and its compatibility with petroleum products.
Synthetic rubber is made by the polymerization of a variety of petroleum-based precursors called monomers. The most prevalent synthetic rubbers are styrene-butadiene rubbers (SBR) derived from the copolymerization of styrene and 1,3-butadiene. Other synthetic rubbers are prepared from isoprene (2-methyl-1,3-butadiene), chloroprene (2-chloro-1,3-butadiene), and isobutylene (methylpropene) with a small percentage of isoprene for cross-linking. These and other monomers can be mixed in various proportions to be copolymerized to produce products with a range of physical, mechanical, and chemical properties. The monomers can be produced pure and the addition of impurities or additives can be controlled by design to give optimal properties. Polymerization of pure monomers can be better controlled to give a desired proportion of cis and trans double bonds.
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Famous quotes containing the words natural, synthetic and/or rubber:
“Saints are simply men & women who have fulfilled their natural obligation which is to approach God.”
—Evelyn Waugh (1903–1966)
“In every philosophical school, three thinkers succeed one another in the following way: the first produces out of himself the sap and seed, the second draws it out into threads and spins a synthetic web, and the third waits in this web for the sacrificial victims that are caught in it—and tries to live off philosophy.”
—Friedrich Nietzsche (1844–1900)
“The idea that information can be stored in a changing world without an overwhelming depreciation of its value is false. It is scarcely less false than the more plausible claim that after a war we may take our existing weapons, fill their barrels with cylinder oil, and coat their outsides with sprayed rubber film, and let them statically await the next emergency.”
—Norbert Wiener (1894–1964)