From Wikipedia: Vulcanization or vulcanisation refers to a specific curing process of rubber involving high heat and the addition of sulfur or other equivalent curatives. It is a chemical process in which polymer molecules are linked to other polymer molecules by atomic bridges composed of sulfur atoms or carbon to carbon bonds. The end result is that the springy rubber molecules become cross-linked to a greater or lesser extent. This makes the bulk material harder, much more durable and also more resistant to chemical attack. It also makes the surface of the material smoother and prevents it from sticking to metal or plastic chemical catalysts.
This heavily cross-linked polymer has strong covalent bonds, with strong forces between the chains, and is therefore an insoluble and infusible, thermosetting polymer. The vulcanization process is a progressive reaction and is therefore allowed for a specified time.
The process is named after Vulcan, Roman god of fire.
A vast array of products are made with vulcanized rubber including ice hockey pucks, tires, shoe soles, hoses and many more.
Hard vulcanized rubber is known as ebonite or vulcanite and is used to make bowling ***** and clarinet mouth pieces.