Building thermally and chemically reversible covalent bonds in vegetable oil based epoxy thermosets. Influence of epoxy–hardener ratio in promoting recyclability

Abstract

Thermoset polymers with permanently cross-linked networks formed via thermally reversible covalent bonds have outstanding self-healing and adaptable properties, combined with very good mechanical properties and solvent resistance. This work reports for the first time the synthesis and characterization of such materials, derived from epoxidized linseed or soybean oils crosslinked with different amounts of 2,2′-dithiodibenzoic acid. The epoxy/hardener ratio was studied as a key parameter influencing the overall process and moreover the network recyclability. The synthesized thermosets showed excellent chemical recycling and mechanical reprocessing abilities. The produced networks were chemically recycled, then the recuperated reprocessed material was found to show no or a small decrease in mechanical properties. These biobased thermosets provide opportunities for the circular use of thermosets.