Preparation and Properties of Dynamic Covalent-Based Epoxidized Soybean Oil-Derived UV-Curable Resin

To develop ultraviolet (UV)-curable resin with excellent mechanical, thermal-resistant and self-healing properties, epoxidized soybean oil was utilized as a bio-based raw material in this paper, and its epoxy groups were ring-opened and modified with methanol and tert-butyl acetoacetate to introduce hydroxyl groups and flexible segments, yielding a functionalized polyol, which was reacted with isophorone diisocyanate to prepare a hydroxyl-terminated polyurethane prepolymer containing dynamic covalent bonds. The prepolymer was further end-capped with hydroxyethyl acrylate to obtain a UV-curable polyurethane acrylate resin. The physico-mechanical properties and self-healing efficiency of the samples were systematically investigated. The results showed that the prepared specimens had efficient self-healing capability and could achieve efficient repair of damaged interfaces through appropriate heat treatment without the need for external catalysts; the onset decomposition temperatures of all the samples were greater than 225 °C, demonstrating good thermal stability; the tensile strength, tensile modulus, flexural strength and flexural modulus could be as great as 31.1 MPa, 393.7 MPa, 29.6 MPa and 851.6 MPa, respectively. All these indicated that the prepared samples had good overall performances. This study provides a new strategy for the design and preparation of self-healing photocurable resins based on renewable resources.