Recyclable, Repairable, and Reshapable (3R) Thermoset Materials with Shape Memory Properties from Bio-Based Epoxidized Vegetable Oils

The preparation of thermosets based on epoxidized vegetable oils (EVOs) involved a peculiar attention in recent years; however, most of them cannot be recycled once cross-linked. In the present work, epoxy thermosetting resins like-vitrimers with dynamic disulfide covalent bonds were prepared by copolymerizing twelve EVOs with 2,2'-dithiodibenzoic acid, as hardener. Here, we show for the first time the reprocessability, repairability, and recyclability properties of EVOs thermosets. The 3R abilities were evaluated in correlation with the EVO epoxy contents, which influence the final thermo-mechanical properties of the recycled material. The virgin versus recycled materials' comparison was studied by FT-IR, DSC, TGA, and DMA, also comparing their swelling ability and high gel content. The study investigates, in addition, the excellent shape memory properties of the reprocessed EVOs/disulfide materials.