Strong, Reusable, and Self-Healing Lignin-Containing Polyurea Adhesives.

Reusable, self-healable, removable, and strong bio-based polyurea adhesives were successfully synthesized via partially substituting polyetheramine with polyetheramine-grafted lignin and introducing a chain extender containing dynamic disulfide bonds. The polyetheramine-grafted lignin endowed the polyurea adhesives with significantly enhanced adhesion strength on either metal or wood substrates by introducing intensive hydrogen bonding interactions; the dynamic disulfide bonds played a key role in the excellent self-healing and reusable performance. The thermostability of polyurea adhesives was also improved by introducing lignin. This work provides a novel approach for the high-value utilization of low-cost lignin in recyclable adhesives with excellent comprehensive performance.