Vulcanization

Vulcanization is a process for hardening rubber by curing it with sulfur and heat, forming cross-links between the polymer chains that make the material more rigid and durable and, unlike most other treatments of thermosetting polymers, generally irreversible. The British inventor Thomas Hancock patented the sulfur-and-heat vulcanization process in the United Kingdom on November 21, 1843, eight weeks ahead of the American Charles Goodyear, who patented essentially the same process in the United States on January 30, 1844, after years of his own independent experimentation. The word vulcanization itself was suggested by William Brockedon, a friend of Hancock's, drawing on the Roman god Vulcan, associated with fire, heat and sulfur, and the process remains the standard way of turning soft natural or synthetic rubber into a durable, useful material.