Sulfur vulcanization been uncertainly as to whether it proceeds in a radical or ionic manner. The reactive sites, often referred to as 'cure sites', are unsaturated groups such as alkenes and allyls. During vulcanization, sulfur bridges are formed between these sites, crosslinking the polymer. These bridges may consist one or several sulfur atoms. Both the extent of crosslinking and the number of sulfur atoms in the crosslinks strongly influences the physical properties of the rubber produced: Sulfur, by itself, is a slow vulcanizing agent and does not vulcanize synthetic polyolefins. Even with natural rubber, large amounts of sulfur as well as high
The Sulphur Institute working with representatives in India to encourage similar growth in sulfur usage. TSI worked with the International Fertilizer Industry Association and the Fertilizer Association of India to provide activities and resources on the use of sulfur in agriculture. TSI serves as a spokesperson for the sulfur industry with its Transportation Regulations and Logistics program. "TSI monitors for proposed changes to regulations impacting transportation and handling of sulfur and sulfur compounds." Their program covers transportation by rail, road, and sea transportation on regional, national, and international levels. The Sulphur Institute holds an international symposium annually titled The Sulphur Institute's Sulphur World