Vulcanized

Vulcanization or vulcanisation is a chemical process for converting natural rubber or related polymers into more durable materials by the addition of sulfur or other equivalent curatives or accelerators. These additives modify the polymer by forming cross-links (bridges) between individual polymer chains. Vulcanized materials are less sticky and have superior mechanical properties. The term vulcanized fiber refers to cellulose that has been treated in a zinc chloride solution to cross-link the cellulose fibers.

Although curing of rubber has been carried out since prehistoric times, the modern process of vulcanization, named after Vulcan, the Roman god of fire, was not developed until the 19th century, mainly by Charles Goodyear. Today, a vast array of products are made with vulcanized rubber, including tires, shoe soles, hoses, and conveyor belts. Hard vulcanized rubber is sometimes sold under the brand name Ebonite or the genericized former brand term "vulcanite", and is used in making articles such as clarinet and saxophone mouth pieces, bowling balls, and hockey pucks.

Although vulcanization is a nineteenth-century invention, the history of rubber cured by other means goes back to prehistoric times. The name of the first major civilization in Guatemala and Mexico, the "Olmec", means "rubber people" in the Aztec language. Ancient Mesoamericans, spanning from ancient Olmecs to Aztecs, extracted latex from Castilla elastica, a type of rubber tree in the area. The juice of a local vine, Ipomoea alba, was then mixed with this latex to create processed rubber as early as 1600 BC. In the Western world, rubber remained a curiosity, although it was used to produce waterproofed products, such as Mackintosh rainwear.

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