High-strength, reprocessable, and degradable bio-based non-isocyanate polyurethanes with dual dynamic covalent bonds

In the pursuit of green, environmental protection, and sustainability, the development of bio-based polyhydroxyurethanes (PHUs) to replace traditional petroleum-based polyurethanes has attracted widespread attention. In this study, new bio-based vanillin-PHU vitrimers (C-PHUs) with hydroxyurethane and imine dual dynamic bonds were synthesized. A new vanillin cyclic carbonate with an aldehyde group (V-C) was prepared from the cyclocarbonation of a vanillin-diol with dimethyl carbonate under normal pressure, and the C-PHUs were prepared from the aminolysis reaction of V-C with two triamines. The maximum tensile strength and elongation at break of the C-PHUs reach 79 MPa and 296 %, respectively, which are at the leading level among present PHUs. Aromatic structure makes the C-PHUs show excellent mechanical properties and relatively high T g . Hydroxyurethane and imine dual dynamic bonds result in good reprocessability and self-healing properties as well as low activation energy of 81.81–101.78 kJ/mol. At the same time, imine bonds enable C-PHUs to degrade at room temperature under acidic conditions, providing an efficient way for the post-waste treatment. Bio-based C-PHUs with excellent mechanical properties, reprocessability, and degradability were prepared successfully.