Sulfur vulcanization a substantial fraction of natural and synthetic rubber. Reclaimed rubber has altered properties and is unsuitable for use in many products, including tires. Tires and other vulcanized products are potentially amenable to devulcanization, but this technology has not produced material that can supplant unvulcanized materials. The main problem is that the carbon-sulfur linkages are not readily broken, without the input of costly reagents and heat. Thus, more than half of scrap rubber is simply burned for fuel. Although polymeric sulfur is unstable and decomposes back to its monomer, it is possible to create stable polymers consisting mostly of sulfur via
Sulfur all organic sulfur compounds smell unpleasant at all concentrations: the sulfur-containing monoterpenoid (grapefruit mercaptan) in small concentrations is the characteristic scent of grapefruit, but has a generic thiol odor at larger concentrations. Sulfur mustard, a potent vesicant, was used in World War I as a disabling agent. Sulfur-sulfur bonds are a structural component used to stiffen rubber, similar to the disulfide bridges that rigidify proteins (see biological below). In the most common type of industrial "curing" or hardening and strengthening of natural rubber, elemental sulfur is heated with the rubber to the point that chemical reactions form disulfide bridges between