A DA-bonded crosslinked epoxy-modified polyurethane elastomer with abrasion resistant, weathering resistant, corrosion-resistant, and self-healing functions

Abrasion, UV exposure, and corrosion negatively impact the structural integrity and lifespan of high-speed trains. To tackle these challenges, there is an urgent need to develop a multifunctional elastomer with properties of abrasion resistance, weather resistance, and corrosion resistance. An epoxy-modified polyurethane elastomer with DA (Diels-Alder) bond cross-linking was successfully prepared to meet these needs. By adjusting the molecular weight of the polyurethane soft segments and the epoxy resin content, it was discovered that PUE-1, with a soft segment molecular weight of 1000 g/mol and an epoxy resin content of 5 wt%, exhibited optimal abrasion resistance, suffering a mass loss of only 9.1 mg after 24 h of abrasion. Furthermore, PUE-1 demonstrated excellent weathering resistance, with a reduction in tensile strength of just 18.6 % after 15 days of accelerated UV testing. Additionally, PUE-1 displayed an impressive adhesion strength of 14.6 MPa, surpassing most elastomers reported in the literature. Thanks to the inclusion of DA bonds, PUE-1 possesses self-healing capabilities, achieving a self-healing efficiency of 77.3 % after 16 h of repair. Moreover, PUE-1 exhibits outstanding corrosion resistance, with its low-frequency modulus increasing by 2 orders of magnitude compared to samples without epoxy resin after 30-day EIS experiments. This work offers valuable insights for the development of multifunctional elastomers that provide abrasion resistance, weathering durability, corrosion protection, and self-healing properties.