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
Union Sulphur Company the Supreme Court, which declined to review the Third Circuit opinion. The competitors were free to use the Frasch Process. The Union Sulphur Company continued to extract sulfur, averaging over 200,000 tons per year from 1905 to 1911 and eventually producing a total of almost 9.5 million tons. Sulfur has many industrial uses, including as sulfuric acid and in the manufacture of explosives, among others. The Union Sulphur Company, as the primary source of sulfur in the U.S. before and during World War I, was critical to the U.S. war effort. As the legal battle over the expiration of its