Vitrimers, invented in 2011, are chemically crosslinked networks characterized by the presence of exchangeable links, a feature that allows to change topology while keeping the integrity of the network. Vitrimers show unusual combination of properties: they are both insoluble and processable, and flow in the same way as glass at high temperature.

This makes them fundamentally recognized as a third and new class of polymeric materials, alongside thermoplastics and thermosets, and on a practical level as a new means of controlling and resolving problems of (re)processing, chemical strength and thermal resistance of materials and composites.