High-Strength, Self-Healing, Recyclable, and Catalyst-Free Bio-Based Non-Isocyanate Polyurethane

Non-isocyanate polyurethanes (NIPUs) from re-newable resources have attracted wide attention because of their remarkable benefits to sustainable development and green production. In this work, a strong, self-healing, and catalyst-free NIPU (ECMP) was prepared based on the hyperbranched bio-based cyclic carbonate (Ec-MTDA) synthesized through catalytic carbonization of 1,8-menthane diamine (MTDA) and CO2. The hyperbranched and rigid structures of ECMP enable improved mechanical properties that a high tensile strength of up to 34.9 MPa can be achieved. Benefiting from the dynamic trans-esterification reaction between the carbamate and hydroxyl groups, ECMP presents favorable self-healing, reprocessing properties, and shape memory. Notably, 91% of the original tensile strength can be recovered after self-healing behavior. In addition, abundant polar groups provide excellent adhesion properties for ECMP with a high shear strength of 7.09 MPa. This study provides a promising strategy for the design of bio-based NIPUs, which broadens their applications in printing, furniture, packaging, and other industries.