Reactive extrusion of vitrimers: A short review

Vitrimers are dynamic covalent polymer networks that combine the mechanical robustness of thermosets with the reprocessability of thermoplastics. Their unique associative bond exchange mechanism enables thermal malleability and stress relaxation while preserving network integrity, offering a promising route toward sustainable, high-performance materials. However, scalable processing of vitrimers remains a key challenge. Reactive extrusion (REX), a continuous, solvent-free method commonly used in polymer manufacturing, has emerged as a powerful technique to synthesize and reprocess vitrimers. This review highlights recent advancements in integrating vitrimer chemistry with reactive extrusion, focusing on diverse dynamic bond systems including trans-esterification, dioxaborolane metathesis, disulfide exchange, silyl ether exchange, and vinylogous urethane exchange. We explore the compatibility of these systems with REX in various polymer matrices ranging from polyesters and polyolefins to bio-based networks and discuss how parameters such as crosslink density, catalyst use, and phase behavior influence processability and material performance. Despite challenges such as limited residence time, degradation risks, and incomplete curing, emerging strategies like pre-vitrimer formation and tailored network design promise to overcome current limitations. By bridging polymer chemistry and process engineering, REX of vitrimers holds significant potential for enabling scalable, recyclable thermoset alternatives aligned with circular economy goals.