Vitrimers: Associative dynamic covalent adaptive networks in thermoset polymers

The vitrimer-thermoset concept represents an important contribution to improve the durability and recyclability of thermoset-systems. The concept of Associative Dynamic Covalent Adaptive Networks (ADCAN), based on thermosetting vitrimers, demonstrates a high level of stress relaxation, self-healing and shape memory properties. In such a "vitrimer" the dynamically fixed crosslink density allows to reprocess the material without loss of macroscopic properties based via a temperature dependent associative exchange. The overall reprocessing can be achieved by purely associative bond-exchange, controlled by its kinetic profile, adjustable via the used catalysts. This review article describes the relevant associative dynamic covalent exchange reaction mechanisms for vitrimers within thermosetting polymers and summarizes the resulting material properties with a final focus on recent applications. Further demands for increased life-cycle times will speed up the necessity for vitrimerthermoset-materials, placing these materials in the focus of future material development concepts.