Lignin-based vitrimers: valorization and utilization of lignin in high-value applications

Abstract

The research efforts directed towards addressing the environmental issues and non-recyclability of conventional plastics has triggered great attention for vitrimers as a new type of renewable plastic. Vitrimers are characterized by dynamic covalent linkages that impart strong chemical resistance and strength similar to that of thermosets, while enabling reprocessability under specific conditions. The past decade has witnessed the development of various vitrimeric chemistries that are applicable to a broad range of bio-based prepolymers with application in vitrimer synthesis. This review aims to provide an overview of the recently reported lignin-based vitrimers, laying emphasis on their thermal–mechanical properties, potential applications based on their properties, and their dynamic bond exchange mechanisms. Furthermore, important features of bio-based vitrimers such as self-healing, shape memory, renewability, and reprocessability will be discussed. Some key modifications of lignin, which are necessary to improve its compatibility with other materials and targeted vitrimeric chemistry, will also be highlighted.