A Green Recyclable Vanillin-Based Polymer (Amide–Imide) Vitrimer

In this paper, a bio-based polyamide imide polymer, PDPD (Polymer of D230, Poly hexa methylene diamide and Dialdehyde vanillin), was synthesized via amine aldehyde condensation reaction. PHMD was prepared from diethyl oxalate (ODE) and 1,6-hexanediamine (HAD), and vanillin was dialyzed to give dialdehyde vanillin (DVA). Then polyether amine D230 was introduced to obtain polyamide prepolymer, and triethyl citrate was used as cross-linking agent to prepare bio-based glass polymer material PDPD through bulk polymerization at high temperature. The thermal stability, glass transition temperature, mechanical properties, and energy storage modulus of PDPD material were investigated through thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and stress-strain curve. Results show that PDPD possesses excellent thermal stability and high mechanical strength, with a 5% thermal decomposition temperature at 288 °C, a stress of 7 MPa, and a strain of 117%. The storage modulus of PDPD in DMA testing can reach up to 2907 MPa. The anti-creep performance of PDPD is good, and the creep level after two repairs is within 40%. Self-healing testing revealed that PDPD maintained its performance after self-healing. The synthesized polymer is also recyclable, making it an attractive option for environmentally conscious applications.