Natural rubber chemical formula

A convenient term for any material possessing the properties of a rubber but produced from other than natural sources. A synthetic version of natural rubber has been available for many years with the same chemical formula, i.e., cis-1,4-polyisoprene, but it has not displaced the natural form. See also Butyl Rubber, Chloroprene Rubber, Ethylene-Propylene Rubber, Nitrile Rubber, Silicone Rubber and Styrene-Butadiene Rubber. 

In 1826, Faraday established the chemical formula of the monomer unit of natural rubber or polyisoprene. 

The product after the first stage contains 35% chlorine, and is rubbery. The second stage product that contains 57% chlorine has no unsaturated groups. Further chlorination results in the final product containing 65.5% chlorine, with the empirical formula -CjgHjjCl -. The final product of chlorination of natural rubber is a pale cream or off-white thermoplastic powder, which is inflammable and highly resistant to chemical attack. 

Silicone, natural, and synthetic rubbers have been used for the fabrication of implants. Natural rubber is made mostly from the latex of the Hevea brasiliensis tree and the chemical formula is the same as that of cw-1,4 polyisoprene. Natural rubber was found to be compatible with blood in its pure form. Also, cross-linking by x-ray and organic peroxides produces rubber with superior blood compatibility compared with rubbers made by the conventional sulfur vulcanization. 

The ideal way to mix continuously would be to have continuous weigh feeders which would continuously feed in the correct ratio to give the desired formula of rubber, chemicals and liquid directly into the continuous rubber mixing machine. However, most rubber formulas have on average 15 different chemicals to make the complete formula, so it is very difficult to do this weighing continuously due to the high cost and varied nature of the chemicals involved. 

Zinc carbonate hydroxide has the chemical formula 2ZnC03.3Zn(0H)2. It occurs naturally as the mineral hydrozincite and is listed in the Colour Index (1971) as Cl 77951. The composition of the commercial product is reported to vary and it may contain zinc oxide (. v.) as an impurity. It is used in the USA as a white pigment, and in the mannfacture of porcelains, pottery and rubber (Merck Index, 1996). 

Latex, synthesized in Germany in World War II in several formula variations,was svibstituted for unavailable natural latex in rubbers and also for drying oils and resins in paints. These, plus designed polymer evolutions from the American Riobber Reserve progreim of several chemical species of latexes, educated the householder to the convenience of water system paints which were far better thein earlier, lime-based, water dispersed paints. 

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