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
Sulfur trioxide in situ from sulfuric acid or is used as a solution in the acid. Along with being a strong oxidizing agent, sulfur trioxide will cause serious burns on both inhalation and ingestion because it is highly corrosive and hygroscopic in nature. SO should be handled with extreme care as it reacts violently with water and produces highly corrosive sulfuric acid. It should also be kept away from organic material due to the strong dehydrating nature of sulfur trioxide and its ability to react violently with such materials. Sulfur trioxide Sulfur trioxide (alternative spelling sulphur trioxide) is the chemical compound with