Self‐healable, weldable, and reprocessable castor oil‐based poly(thiourethane‐urethane) networks

Abstract Vegetable oil‐based polyurethane (PU) vitrimer is of significance for sustainable industrial development; however, development of vegetable oil‐based PU vitrimers with high mechanical properties and excellent malleability by a facile synthetic process remains a challenge. Herein, a series of versatile, self‐healable, weldable, and recyclable castor oil‐based poly(thiourethane‐urethane) networks are constructed by one‐pot reactions. Double bonds and hydroxy groups in castor oil can react with thiol in 2,2′‐(1,4‐phenylene)‐bis[4‐mercaptan‐1,3,2‐dioxaborolane] (BDB) and isocyanate in 4,4′‐diphenylmethane diisocyanate (MDI), respectively, as well as a reaction between the thiol of BDB and the isocyanate of MDI, which gives the castor oil‐based poly(thiourethane‐urethane) vitrimers. The obtained bio‐based networks are characterized by Fourier transform infrared (FTIR) and dynamic mechanical analysis (DMA) measurements. The castor oil‐based vitrimers show high thermostability ( T 5d > 312°C) due to the incorporation of rigid BDB and MDI with benzene group in the networks. Meanwhile, the castor oil‐based networks have been proved to possess more excellent functions in self‐healing, welding, shape memory, and reprocessing capabilities at moderate temperatures due to the dynamic boronic ester bonds. This work would be beneficial to developing of versatile vegetable oil‐based poly(thiourethane‐urethane) materials through a facile approach.