Biobased Networks from Lignin/Cellulose via Diels-Alder Click Chemistry

Thermosets play a key role in modern plastic and coating industries. However, the cross-links responsible for their outstanding properties, such as improved tensile strength and chemical and thermal resistance, render them unable to undergo reprocessing or recycling. Herein, biobased thermosets were prepared from lignin and cellulose via the Diels-Alder (DA) click reaction, thereby providing fully biobased polymer thermosets while envisioning the properties of dynamic networks. Furan and maleimide moieties were attached to soda lignin and cellulose. DA reactions were then carried out using different combinations of functionalized lignins and bismaleimide, forming a cross-linked network while simultaneously enabling a reversible control over thermally induced de-cross-linking and re-cross-linking. In contrast, thermoreversibility was not achieved when associating both lignin and cellulose via DA-based cross-links, even though mild reaction temperatures and lower degrees of cross-linking were considered. Ultimately, the study contributed to widening the use of furan-maleimide DA click chemistry for the preparation of sustainable materials, providing insights into a green and versatile platform that may be considered for future applications.