Elastomers consists of long lightly cross-linked molecules.
Common elastomers are:
Elastomers may be strengthened by vulcanization process (heat treatment in presence of chemical agents).
Vulcanization results in increase of cross-linking of the molecules.
Vulcanized elastomers are elastic for small deformations.
Vulcanization produces cross-links which make impossible shaping material. Therefore most of elastomers are shaped before cross-linking.
However there are some elastomer materials which are not cross-linked when heated. These elastomers may be reversibly remolded by heating many times (like Thermoplastics).
Such kind of elastomers is called Thermoplastic Elastomers.
Common thermoplastic elastomers are: