Vitrimers: Permanently crosslinked polymers with dynamic network topology

The study of synthetic organic polymers rapidly expanded since Staudinger's recognition of the covalent structure of macromolecules. Today, these materials are far from just an academic concept-they are produced industrially and have become ubiquitous in everyday life because of their low cost and desirable physical properties. Nevertheless, a difficult choice between durability and reprocessability continues to hamper efforts to design synthetic organic polymers to be more recyclable. A new class of materials, vitrimers, has emerged as an intriguing approach to circumvent this tradeoff. Vitrimers are permanent networks of polymer chains connected via dynamic covalent bonds, which allow the network to change its topology while maintaining a constant number of chemical bonds at all temperatures. Characterized by both high mechanical performance and facile processing, vitrimers are well positioned to transition from academic labs to industrial production. The aim of this Trend article is to review the concept of vitrimers, describe their most unique properties, and present our outlook on outstanding challenges that must be met to realize vitrimers as a next generation solution for recyclable high performance materials. (C) 2020 Elsevier B.V. All rights reserved.