Vulcanisation is a chemical-physical transformation in which predominantly plastic rubber changes into a rubber-elastic state. This process, which takes place by linking macromolecules at their reactive sites, is called cross-linking or vulcanisation.

In 1839, Charles Goodyear invented the process of vulcanisation, more or less by scientific accident. After adding various materials and chemicals to rubber, a sulphur-rubber mixture fell on a hot cooker top and the result was a dry and permanently elastic substance. When heated, the rubber mixed with sulphur turned into a new substance, rubber. With this, Goodyear had discovered vulcanisation.

Vulcanisation therefore requires a vulcanising agent. The oldest and most common vulcanising agent is sulphur. The classic example of vulcanisation is the sulphur vulcanisation of natural rubber.