Vulcanization is a manufacturing process for plastic components with elastic properties. Natural or synthetic rubbers are used as input. If they are initially regarded as thermoplastics, they become elastomers through vulcanization.
This transition is caused by the creation of additional cross-links between the macromolecules of the material.
Instead of a permanent change in shape as a reaction to an external force, these cross-links allow an elastic restoring moment to occur. Vulcanization turns caoutchouc into rubber.