Self-Healing Polyurethane Elastomers with High Mechanical Properties Based on Synergistically Thermo-Reversible and Quadruple Hydrogen Bonds

Abstract

It is still challenging and attractive to prepare polyurethane (PU) materials with excellent self-healing ability while improving their mechanical properties and high ductility. Here, a multifunctional linear PU supramolecular elastomer was successfully prepared by introducing a cross-linking network of quadruple hydrogen bonds and thermo-reversible Diels–Alder bonds and rigid ring structure to the linear backbone. The results exhibited that the obtained PU elastomer displayed a high tensile strength (6.30 MPa), elongation (1957.84%), toughness (84.48 MJ/m3), and excellent repair efficiency (93.33%). The quadruple hydrogen bonds from 5-(2-hydroxyethyl)-6-methyl-2-aminouracil and thermo-reversible Diels–Alder bonds from the conjugated reaction of 4,4′-bismaleimide diphenylmethane with furfuryl alcohol, due to its synergetic dual reversible bonds, formed the PU elastomer that possessed excellent mechanical, self-healing, shape recovery, and reprocessing properties. The prepared multifunctional PU can be used as a substrate for flexible conductive materials or as conductive composite material with conductive materials, which can self-repair many times when the surface is damaged, can be recycled, and greatly improve the service life of the material. Therefore, the prepared multifunctional high-performance self-healing PU materials have potential applications in several fields.

Highly Adhesive and Tough Thermoplastic Polyurethanes Using a Furandicarboxamide Rigid Chain Extender with Noncovalent Interactions

“…The material exhibited excellent tensile strength, toughness, and self-healing properties at room temperature. Recently, some works on introducing special dynamic bonds including hydrogen bonds, − disulfide bonds, , metal–ligand coordination, , etc., into the PU molecular chain through the chain extender to achieve reinforcement, toughening, and special applications of materials have received extensive attention.…”

Self-Healing Elastomers with Unprecedented Ultrahigh Strength, Superhigh Fracture Energy, Excellent Puncture Resistance, and Durability Based on Supramolecule Interlocking Networks Formed by Interlaced Hydrogen Bonds

“…The PUU–OD–AD-1 elastomer, with an extremely low weight of only 0.04 g, can easily lift a 5 kg dumbbell, which is 125,000 times its weight (Figure b), when the mass of PUU–OD–AD-1, a 20 kg dumbbell, was easily lifted by stretched PUU–OD–AD-1 (Movie S1), demonstrating the extraordinary mechanical property of PUU–OD–AD-1. Meanwhile, by comparing different elastomers and some plastics reported by some literature (Figure c), ,,,− ,,,,− the PUU elastomers in this work exhibited ultrahigh mechanical properties. Except comparing with the PI–PUU composite elastomer, the PUU elastomers of our work exhibited the highest tensile strength in the field of pure PUU or PU elastomers.…”

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

“…10−13 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, 14,15 T h i s c o n t e n t i s Diels−Alder (D−A) reactions, 16,17 boronic ester bonds, 18,19 acyl hydrazone bonds, 20 and diselenide bonds, 21 as well as noncovalent reversible bonds, such as hydrogen bonds, 22 coordination bonds, 23 π−π stacking, 24−26 ionic bonds, and others. 27 Among them, the hydrogen bond is a type of dipole− dipole interaction, and its strength depends on the nature of the donor and acceptor.…”

“…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.…”