Polymer architecture via abstraction of a hydrogen, can create a mid-chain growth site. Branching can be quantified by the branching index. An effect related to branching is chemical crosslinking - the formation of covalent bonds between chains. Crosslinking tends to increase T and increase strength and toughness. Among other applications, this process is used to strengthen rubbers in a process known as vulcanization, which is based on crosslinking by sulfur. Car tires, for example, are highly crosslinked in order to reduce the leaking of air out of the tire and to toughen their durability. Eraser rubber, on the other hand, is not
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