Synthesis of self‐healing polyurethane urea‐based supramolecular materials

Abstract

Supramolecular polyurethane ureas are expected to have superior mechanical properties primarily due to the reversible, noncovalent interactions such as hydrogen bonding interactions. We synthesized polyurethane prepolymers from small molecular weight of poly(tetramethylene ether)glycol and isophorone diisocyanates, which were end capped with propylamine to synthesize polyurethane ureas with high contents of urea and urethane groups for hydrogen-bonding formations to facilitate self-healing. The effects of polyurethane urea molecular weight (3000 M n 9000), crosslinking, and cutting direction were studied in terms of thermal, mechanical, and morphological properties with an emphasis on the selfhealing efficiency. It was found that the thermal self-healability was more pronounced as the molecular weight of polyurethane urea decreased, showing a maximum of more than 96% with 3000 M n when the sample was cut along the stretch direction.Recently, thermoresponsive self-healing PUs based on the Diels-Alder reaction between furan and maleimide moieties were reported, where the shape-memory effect was used to autonomously close the crack. 20,21

Synthesis of self-healing waterborne polyurethanes containing sulphonate groups

“…[5][6][7][8][9][10] This approach allows materials to repair themselves automatically aer sustaining damage. 11,12 The self-healing potentials of materials depend strongly on their intrinsic and extrinsic properties. Intrinsic self-healing materials achieve repair through the inherent reversibility of chemical bonds and physical interaction between the damaged interfaces, and extrinsic self-healing materials repair themselves via intentionally pre-embedded healing agents.…”

“…light, heat, static load, and pH variation). 11,[13][14][15][16][17] In addition, a temporary local increase in the mobility of the molecular chains also has a crucial inuence on an efficient healing process. 18 Healable polyurethane is one of the systems that exhibits repairing via supramolecular interaction.…”

Moisture‐mediated intrinsic self‐healing of modified polyurethane urea polymers

“…Polymers with urethane and urea units are well known as materials with stimuli responsive and self‐healing properties . The self‐healing efficiency based on supramolecular interactions depends strongly on the urea group density, the molecular weight of the polyurethane urea, and the crosslinking density.…”

“…The self‐healing efficiency based on supramolecular interactions depends strongly on the urea group density, the molecular weight of the polyurethane urea, and the crosslinking density. Best self‐healing performance in a supramolecular polyurethane system was observed for short polymer chain as a sufficient diffusion and chain mobility are advantageous . Leibler and coworkers pursued a similar approach dealing with a supramolecular polymeric system consisting of urea moieties enabling hydrogen bonding .…”

An Easily Accessible Self‐Healing Transparent Film Based on a 2D Supramolecular Network of Hydrogen‐Bonding Interactions between Polymeric Chains

“…[19][20] Noncovalent interactionss uch as hydrogen bonding have been implemented in the investigation of supramolecular dynamers. [16,17,[21][22][23][24][25] They offer adirect pathway for introducing intrinsics elf-healing features into materials, [3] so that an increase in the number of hydrogen bonds within am olecular framework would enhancet he chance of autonomic non covalent interactions and their ability to undergo self-repairing without the addition of any externalagent.…”