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

Abstract

Non-isocyanate polyurethanes (NIPUs) from renewable 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 biobased cyclic carbonate (Ec-MTDA) synthesized through catalytic carbonization of 1,8-menthane diamine (MTDA) and CO 2 . 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 transesterification 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.

Imine-Containing Epoxy Vitrimer Cured by Active Ester: Properties and Theoretical Analysis

“…Observing the self-healing process of materials often involves taking optical photographs of scratch healing. ,,− Elastomeric materials, which typically exhibit high elongation at break (>100%) and low tensile strength (<10 MPa), tend to achieve nearly perfect self-healing results, with scratches becoming virtually invisible after healing. On the other hand, harder materials, characterized by lower elongation at break (<10%) and higher tensile strength (>50 MPa), usually exhibit a thin seam after scratch healing.…”

“…The polymers that have been studied for their self-healing properties are usually elastomers, such as polyurethanes, which have excellent self-healing properties. − The macroscopic scratch healing experiment is a conventional way to characterize self-healing properties, where the cut polymer recovers after a period of heating, − and the scratch healing experiment has been widely used to study vitrimers. ,,− However, some experiments do not achieve nearly perfect healing results as in the case of self-healing elastomers, and the vast majority of epoxy vitrimer still remains a thin seam after self-healing. ,− Therefore, the self-healing performance of the vitrimer needs to be studied more thoroughly.…”

Tough and Self-Healing Waterborne Polyurethane Elastomers via Dynamic Hydrogen Bonds Design for Flexible Conductive Substrate Applications

“…However, the weak dynamic nature of the internal crystallinity, entanglement, and strong covalent bonds often hinder the migration ability of polymer chains, making it difficult to achieve self-repairing performance. − In recent years, there has been extensive research and reporting on incorporating reversible bonds into polymer chains to confer repairability to materials. These include covalent reversible bonds, such as disulfide bonds, , Diels–Alder (D–A) reactions, , boronic ester bonds, , acyl hydrazone bonds, and diselenide bonds, as well as noncovalent reversible bonds, such as hydrogen bonds, coordination bonds, π–π stacking, − ionic bonds, and others . Among them, the hydrogen bond is a type of dipole–dipole interaction, and its strength depends on the nature of the donor and acceptor.…”

Functional and Environmental Friendly Polyimine Elastomer Based on the Dynamic Covalent Network for a Flexible Strain Sensor

“…With the rapid development and application of flexible sensors, a crucial problem that must be paid sufficient attention to by all countries is the direct discarding and burying of numerous worn-out flexible sensors that seriously threaten the natural environment and human health. − Therefore, controllable degradability is essential to prepare next-generation and environmentally friendly flexible sensors. To the best of our knowledge, only a few works on self-healing and degradable elastomers have been reported in recent years.…”