Tough and Fast Light-Controlled Healable Lignin-Containing Polyurethane Elastomers

In this work, tough and fast light-controlled healable lignin-containing polyurethane elastomers (LPUes) with a dynamic dual-crosslinking network were successfully synthesized. The network consisted of dynamic noncovalent bonds (hydrogen bonds and Zn2+-based coordination bonds) and dynamic carbamate bonds, which endowed LPUes with excellent mechanical properties (31.4 MPa, 1528%), reprocessability, and healing properties. After 4 times of reprocessing, the retention ratios of tensile strength and elongation at break for LPUes maintained above 85 and 95%, respectively. The incorporation of Zn2+-based coordination bonds significantly enhanced the photothermal conversion capability of LPUes, with the maximum surface temperature reaching above 160 °C in 2 min under the near-infrared (NIR) illumination of 1.2 W/cm2. The prepared LPUes exhibited rapid and outstanding light-controlled healing performance with 98% healing efficiency of mechanical properties under 10 min of NIR irradiation. This work demonstrated the novel application of biomass lignin in recyclable and light-driven smart polyurethane elastomers with good mechanical properties.