Degradable and programmable shape-color dual-response tung oil-based foams with dynamic covalent bonds

The application of epoxy foams is limited by their non-biobased raw materials and challenging degradation. To address these issues, this study prepared catalyst-free, self-healing, and degradable tung oil-based foams (VF-X) based on dynamic ester exchange. These foams were developed using the latent foaming-curing agent isophorone diamine carbamate (IPDAC), along with triglycidyl ester of eleostearic acid maleic anhydride adduct (TEMA) and isophorone diamine (IPDA) as raw materials. The resulting foams demonstrated favorable mechanical properties (compressive strength of 3.55 MPa) and notable thermal stability. With dynamic hydroxyl ester bonds and self-catalytic tertiary amine groups, these foams exhibited outstanding self-healing performance (withstand a weight of 500 g), rapid stress relaxation, excellent degradability in ethanolamine, and triple-shape memory properties without requiring additional catalysts. Leveraging these features, a visually programmable shape-color dual-response smart foam (VF-TC) was developed using thermochromic microcapsules (TCM) doped in tung oil-based foams. These high-performance multifunctional foams can be easily prepared, offering promising prospects for smart applications in precise local shape and color modulation, environmental sensing, and high‑temperature warning systems.