Polymer such as rubber, suberin, melanin and lignin. Naturally occurring polymers such as cotton, starch and rubber were familiar materials for years before synthetic polymers such as polyethene and perspex appeared on the market. Many commercially important polymers are synthesized by chemical modification of naturally occurring polymers. Prominent examples include the reaction of nitric acid and cellulose to form nitrocellulose and the formation of vulcanized rubber by heating natural rubber in the presence of sulfur. Ways in which polymers can be modified include oxidation, cross-linking and endcapping. Especially in the production of polymers the gas separation by membranes has acquired increasing
Texas Gulf Sulfur Company by the Frasch Process to that date. The company entered the Mexican market in 1949, with its subsidiary Cia. Exploradora del Istmo, S.A. Headquarters were established in Coatzacoalcos in 1950, and production from their Nopalapa plant commenced in 1957. By 1958, Texas Gulf had produced 69,490,00 tons of sulfur, which was 53.7 percent of the total Frasch sulphur production from 1895 through 1957. In April 1972, the company became TexasGulf. In 1981 the company was acquired by Elf Aquitaine. Texas Gulf Sulfur Company The Texas Gulf Sulphur Company was one of the largest sulfur mining companies in the world from