Recent advances and challenges in the mechanical and chemical recycling of vitrimers and fibre-reinforced vitrimer composites: A review

Vitrimers, a class of covalent adaptable networks, have emerged as a promising alternative to traditional thermoset and thermoplastic polymers, owing to their unique reprocessability and recyclability. This review provides a comprehensive overview of mechanical and chemical recycling methodologies for vitrimers and their fibre-reinforced composites, highlighting recent advancements and innovations in the field. Firstly, the review classifies vitrimers based on their structure and dynamic covalent mechanisms and summarises their main properties. Subsequently, it gives an overview of the conditions and outcomes of both mechanical and chemical recycling processes for vitrimers. Then, after summarising the processing methods of vitrimer composites, it explores mechanical composite recycling techniques, which, while straightforward, often lead to diminished mechanical properties due to fibre length reduction. In contrast, chemical composite recycling methods demonstrate superior potential for preserving fibre integrity and recovering original monomers for closed-loop synthesis. Key studies showcasing successful recycling processes are discussed, underscoring the importance of developing closed-loop systems to enhance sustainability in material applications. Ultimately, this review aims to highlight the critical advancements in recycling strategies for vitrimers, positioning them as a vital component of sustainable composite material development.