Synthesis and Characterization of Fully Biobased Nonisocyanate Polyurethane with Excellent Mechanical Properties, Recyclability, and Clusteroluminescence

Nonisocyanate polyurethanes (NIPUs) synthesized via cyclic carbonates and amines offer a sustainable alternative but often suffer from low performance when derived entirely from biobased feedstocks. This work introduces high strength and recyclable fully biobased NIPUs using resveratrol (RE)-derived cyclic carbonate and magnolol-based quaternary cyclic carbonate (MAG-QCC) to cure with Priamine 1074. By introducing rigid aromatic and conjugated structures, resveratrol-based polyhydroxyurethanes (REPHUs) and magnolol-based polyhydroxyurethanes (MAGPHUs) achieved the highest tensile strength of 31.4 MPa and a break elongation of 161%. After thoroughly investigating the molecular structures of two polyhydroxyurethane (PHUs), it was found that the planar conjugated aromatic structure of resveratrol in REPHUs, characterized by dihedral angles of 179.78 and 179.90°, leads to superior tensile strength and higher T_g compared to MAGPHUs, which are influenced by magnolol’s distorted biphenyl configuration with a dihedral angle of 39.72°. Additionally, dynamic carbamate and hydroxyl bonds enable efficient physical remolding, retaining more than 83% of the original tensile strength after reprocessing. The PHU network can be chemically degraded by alcoholysis, enabling closed-loop recycling. Notably, these materials exhibit fluorescence due to carbamate-induced clusteroluminescence, with the fluorescence intensity remaining constant even under deformation, demonstrating the potential for anticounterfeiting applications. This work explores an environmentally friendly way to synthesize high strength, recyclable cross-linked NIPUs from biobased sources, which broadens their applications in fields such as elastomers, packaging, and anticounterfeiting.