A super strong polyurethane elastomer with efficient self-healing performance enabled by partially mixing reversible hard domains

Abstract

The reversible chain extender Diels-Alder-diol (DA-diol) containing thermally dissociable Diels-Alder adducts (DA adducts) was synthesized and combined with 1,4-butanediol (BDO) as composite chain extenders used for preparing a transparent polyurethane elastomer (DAPU) with high mechanical strength and efficient self-healing ability by partially mixing reversible hard domains. The optimal DAPU occupies a desired high tensile strength of 65 MPa, and its elongation at break and toughness are of 1050 % and 216 MJ·m−3, respectively. Meanwhile, the DAPU-0.2 elastomer heals at 110 °C for 2 h with a healing efficiency of 95%. The desirable mechanical strength and efficient self-healing ability are attributing to the BDO chain extended hard segments ensure the high strength at room temperature, while DA-diol chain extended hard segments endow the as-prepared DAPUs with self-healing ability at an elevated temperature. This work overall points to a strategy in designing self-healing polyurethane elastomers with markedly improved mechanical strength by partially mixing reversible hard domains.