Biobased vitrimers: Towards sustainable and adaptable performing polymer materials

In the last decades, Covalent Adaptable Networks (CAN) appeared as an innovative polymer family, able to bridge the gap between thermoplastics and thermosets. CAN rely on the use of dynamic covalent chemistry applied to crosslinked polymer networks. In CAN, the covalent linkages that constitute the network are dynamic and can be reshuffled within the network under stimulus, such as heat or light. In 2011, Leibler and co-workers enriched this field introducing the concept of vitrimers, crosslinked polymers in which the covalent linkages can be redistributed within the network upon heating thanks to associative exchange reactions, while maintaining the network integrity. Upon increasing the temperature, exchange reactions are fast enough to allow the network to flow, although the crosslink density remains constant. The name of this family of materials underlines the analogy in viscosity behavior with vitreous silica. Since this seminal work, many research groups focused on consolidating the theoretical background, (re)discovering various dynamic chemistries for the development of vitrimers and exploring the amazing properties of this new class of polymers, such as recyclability, shape memory, self-healing or stimuli responsiveness. Intriguing opportunities arise from combining the concept of vitrimers with the attractive features of biobased polymers as a platform to enable the design of high-performance and sustainable materials. The last five years have thus seen a huge increase of publications related to biobased vitrimers. This review aims at giving a comprehensive overview of the state-of-the-art in this emerging but already very dynamic field. It is also intended to highlight the attention of the vitrimer community on the need to develop sustainable materials, by showing how biobased building blocks can be employed to synthesize high-performance and innovative vitrimers. After summarizing the main vitrimer properties, we herein propose a classification of biobased vitrimers based on their main renewable constituent, that we believe could help the future categorization and advancement on this hot research topic.