Bio-based polyurethane vitrimer with imine bonds: Excellent thermo-mechanical properties and heat recovery

Preparation of vitrimer with excellent performance from biomass feedstock can effectively reduce the waste of fossil fuels and the pollution problem to the environment. In this paper, vanillin (VAN) and 4-amino-3-methylphenol, which are biobased raw materials, were used to prepare the imine-bonded diol AMV-OH in a one-step process, which was incorporated into the main chain of vitrimer polymer, and a series of imine-bonded vitrimer materials AMV-V was obtained by using pentaerythritol tetra-3-mercaptopropionate (PETMP) as a cross-linking agent. The mechanical property analysis, solvent resistance analysis, DSC thermal analysis, DMA analysis and self-repair characterization showed that AMV-V exhibited good thermo-mechanical properties (the highest initial degradation temperature was 246 °C with a Tg value of 17 °C). The results showed that specific mechanical properties could be obtained by adjusting the contents of PETMP and AMV-OH, among which the best tensile properties were obtained at 10 mmol of AMV-OH, with a tensile strength of 8.03 MPa and an elongation at break of 316.79 %. Meanwhile, the AMV-V samples were able to achieve self-healing properties under milder conditions (100 °C, 10 MPa repair for 1 h) and had a high self-healing efficiency (H=94.80 %, R=83.72 %).