Tough polyurethane elastomers with high strength and rapid healing ability

Abstract

Polymers are often susceptible to premature failure due to various physical damages. Incorporation of reversible disulfide bonds with sufficient chain diffusion in polyurethane (PU) elastomers endows them with good healable and recyclable properties, effectively prolonging their service life. However, such healable elastomers frequently exhibit poor toughness and strength. Here, a series of disulfide-containing linear poly(urea-urethane)s are facilely fabricated using 4,4′-dithiodianiline (DTDA) and adipic acid dihydrazide (AD) as chain extenders. The produced elastomer with hierarchical hydrogen bonds has a high tensile strength (60.24 MPa), strain (1489.2%) and toughness (257.24 MJ m⁻³), respectively. Within only 5 h, isopropyl alcohol-assisted healing at 30 °C partially regains tensile strength (44.4 MPa), strain (1254.4%) and toughness (179.52 MJ m⁻³). The combination of hierarchical hydrogen bonds and disulfide bonds allows the achieved elastomer to maintain high mechanical properties and a healing efficiency of approximately 80%. This study facilitates the design and fabrication of PU elastomers with high mechanical performance and healing efficiency.