Functional epoxy vitrimers and composites

From cars to airplanes, from household appliances to indoor ornaments, from biomedical devices to factory equipment, epoxy resins have been deeply rooted in modern society. But at the same time, they also bring about a lot of wastes after use due to their insoluble and infusible nature. Vitrimer opens up great opportunities towards to a sustainable society by producing reprocessable epoxies and even thermosets. Epoxy vitrimers are not only the first reported vitrimers, but also the most studied vitrimers. Epoxy vitrimers are reversible covalently crosslinked networks with dynamic covalent bonds, combining excellent mechanic properties of thermosets with reprocessability of thermoplastics. Moreover, the exchangeable network endows vitrimers with excellent reprocessing, self-healing, welding, reshaping and recycling properties. So vitrimers are hopeful to replace traditional thermosets for a wide range of applications in aerospace materials, electronic devices, consumer products of daily life and so on. This review summarizes recent advances in epoxy vitrimer research. The classification and fabrication of epoxy vitrimers and their composites are thoroughly discussed. New properties of epoxy vitrimers brought by the dynamic covalent bonds are also reviewed in-depth. Their potential applications are subsequently explored and summarized.