Biobased and aromatic Covalent Adaptable Networks: When architectures meet properties, within the framework of a circular bioeconomy

Abstract

In the current context of environmental emergency, the need for sustainable materials with controlled end-of-life is paramount. Covalent Adaptable Networks (CANs) are a novel class of polymers offering a unique solution by combining the main advantages of thermosets and thermoplastics such as high mechanical performance and recyclability. Sustainable feedstocks, such as biobased compounds from biomass represent nowadays prime alternatives to fossil-based chemicals. Consequently, aromatic-rich renewable resources, owing to their abundances and structural variety, are feedstocks of choice in the design of materials combining performance, sustainability, and circularity. Then, the substitution of fossil-based raw materials with biobased compounds for the preparation of CANs is improving, among which aromatic structures, such as lignins, tannins, cashew nutshell liquid or furan, provide unprecedented features and properties. After a description of CANs general features and the presentation of available biobased aromatic feedstocks, an overview of recent advances in the synthesis of biobased aromatic networks is presented. An emphasis is placed on the opportunity offered by the aromatic building blocks functional groups to implement dynamic covalent chemistries. Subsequently, an understanding on the benefits of aromaticity on specific properties required for targeted applications, including sensors, adhesives, flame retardants, biomedical devices, or coatings, is proposed. All these proving the design of biobased and aromatic CANs to be a considerable step towards for a more sustainable future in the frame of a circular bioeconomy.