Fully biomass-derived polyurethane based on dynamic imine with self-healing, rapid degradability, and editable shape memory capabilities

Abstract

In this study, a novel bio-based diol containing imine dynamic bonds (Vanp2) were synthesized using vanillin and bio-based 1,5-pentanediamine. Vanp2 was then introduced into the cross-linking network of betulin-based polyurethanes to obtain betulin-based polyurethanes containing covalent adaptive networks (CANs). Imine dynamic bonds within CAN endowed these betulin-based polyurethanes with self-healing, re-processability, degradability, and editable shape memory functionalities. Meanwhile, the mechanical and thermal properties of these fully bio-based polyurethane materials were characterized. The maximum tensile strength reached 9.5 MPa, while the maximum strain at break was 248 % and the maximum toughness was 13.2 MJ/m³. Thermal decomposition temperature was greater than 300 °C. Since the imine structure could be dissociated under acidic conditions, these polyurethanes could be rapidly degraded in a mixed acid solution at 50 °C in 4 h. This study demonstrated a strategy for synthesizing betulin-based polyurethane elastomers containing CAN using only bio-based feedstock.