Covalent adaptable networks derived from itaconic acid-based epoxy and sulfur: Facile synthesis and applications in adhesives and carbon fiber composites

Abstract

Design of covalent adaptable networks (CANs) that avoid high costs and complex preparation procedures is critical for sustainable development. Herein, a recyclable and degradable epoxy-sulfur CAN (E_xS_y) was prepared by mixing bio-based epoxy and sulfur under solvent- and catalyst-free conditions. The epoxy was derived from the abundant and inexpensive bio-resource itaconic acid, and sulfur is a naturally occurring and abundant by-product of oil and gas desulfurization. The resulting E_xS_y exhibits surprisingly tunable properties, including excellent tensile strength (∼65 MPa) and creep resistance, surpassing those of previously reported CANs prepared via inverse vulcanization. Furthermore, E_xS_y has potential applications in the adhesive and carbon fiber composite fields, enabling reclamation of carbon fibers. This work presents a sustainable and cost-effective strategy for developing high-performance CANs using bio-based and industrial by-product feedstocks, and the reuse of carbon fibers contributes to circular economy principles, reducing waste and resource consumption in material applications.