Biobased Networks\nfrom Lignin/Cellulose via Diels–Alder\nClick Chemistry

Thermosets play a key role in modern plastic and coating\nindustries.\nHowever, the cross-links responsible for their outstanding properties,\nsuch as improved tensile strength and chemical and thermal resistance,\nrender them unable to undergo reprocessing or recycling. Herein, biobased\nthermosets were prepared from lignin and cellulose via the Diels–Alder\n(DA) click reaction, thereby providing fully biobased polymer thermosets\nwhile envisioning the properties of dynamic networks. Furan and maleimide\nmoieties were attached to soda lignin and cellulose. DA reactions\nwere then carried out using different combinations of functionalized\nlignins and bismaleimide, forming a cross-linked network while simultaneously\nenabling a reversible control over thermally induced de-cross-linking\nand re-cross-linking. In contrast, thermoreversibility was not achieved\nwhen associating both lignin and cellulose via DA-based cross-links,\neven though mild reaction temperatures and lower degrees of cross-linking\nwere considered. Ultimately, the study contributed to widening the\nuse of furan-maleimide DA click chemistry for the preparation of sustainable\nmaterials, providing insights into a green and versatile platform\nthat may be considered for future applications.