Eco-friendly epoxy resin derived from tung oil and their sustainable recycling

Eco-friendly plastics are an emerging class of sustainable polymers. However, the process of developing high-performance sustainable polymers often requires the preparation of high-purity monomers from less pure biomass feedstocks. This process is not only complex, but also makes the bio-based feedstock less atom-economical, resulting in higher product costs. In this study, it is proposed to develop cyclic epoxy monomer from tung oil (TO), which are reacted with citric acid (CA) in simple curing reaction to prepare tung oil-based epoxy resins with sustainable recycling properties. These epoxy resins are thermally stable and possess tunable mechanical properties. The dynamic reversible covalent bonding of β-hydroxy esters introduced in the crosslinked network gives the polymer both reprocessable and chemically recyclable properties. In addition, the abundant hydroxyl are able to produce a variety of non-covalent interactions with the adherent substrate, thus exhibiting excellent adhesive properties. The combination of plant oil, thermoplastic-like behavior, and sustainable recycling provides new ideas for the development of new plant oil-based eco-friendly polymer materials.