Bio-Based, Recyclable and Self-Healing Polyurethane Composites with High Energy Dissipation and Shape Memory.

Rubber composites make an important contribution to eliminating vibration and noise owing to their unique viscoelasticity. However, it is important to find alternative bio-based products with high damping properties owing to the shortage of petrochemical resources and poor performance. The ability to self-heal is an additional characteristic that is highly desirable because it can further increase the service life and safety of such products. In this study, a bio-based polylactic acid thermoplastic polyurethane (PLA-TPU) and its composites (PLA-TPU/AO-80) are synthesized. The reversible sacrificial hydrogen bonds in the composites increase the peak value of the loss factor (tan δ max ) from 0.87 to 2.12 with a high energy dissipation efficiency of 99% at 50% strain. After being heated for 15 min, the healed sample recovers 81.98% of its comprehensive mechanical properties due to the reorganization of the hydrogen bonds. Its tensile strength remains at 93.4% after recycling five times. Moreover, its shape memory properties show a response temperature close to the human body temperature making it an ideal candidate for medical applications.