Light Cured Bio-Based Self-Healing Polyurethane Coating Based on Imine Bond

Although bio-based polyurethane materials have attracted much attention due to their characteristics such as renewable and long service life conventional polyurethane materials do not have self-healing properties due to structural limitations, leading to their limited application. Imine bond is a kind of dynamic and reversible covalent bond, which can self-heal damaged materials under mild conditions. Based on this, this work utilized p-phthalaldehyde and poly (propylene glycol) bis (2-aminopropyl ether) to prepare T-NH monomers containing imine bonds. Subsequently, four kinds of bio-based polyurethanes containing T-NH were synthesized from castor oil, epoxy soybean oil, glycerol monostearate, and Sorbitan monooleate under UV conditions. The self-healing performance of bio-based polyurethane materials containing imine bonds was evaluated through optical microscopy and mechanical properties. The results showed that the coating had certain self-healing properties at room temperature, and the self-healing efficiency of the coating was greatly improved when heated to 50°C. Among them, the polyurethane material prepared from glyceryl monostearate had the best self-healing ability, with a self-healing efficiency of 90% and a healing cycle of 4 times. This work not only enhanced the added value of biomass materials but also provided a reference for the preparation of polyurethane materials with self-healing properties.