Design, fabrication and characterization of dynamic covalent polymer networks containing reversible Diels-Alder adducts derived from vegetable oil and furfural

The exploration of novel bio-based functional polymers has high application value and confirms to sustainable development strategies following the increasing shortage of fossil resources. In this research, several different recyclable bio-based dynamic covalent polymer networks (DCPNs) containing dynamic Diels-Alder bonds from vegetable oil and furan were designed and fabricated via a simple preparation process. The reprocessability, shape memory, molecular structures, thermal properties and mechanical properties of the DCPNs were all investigated. 1H nuclear magnetic resonance (1H-NMR) and Fourier transform infrared spectroscopy (FTIR) analysises demonstrated the target reactive products were all successfully synthesized. Variable-temperature FTIR and differential scanning calorimetry revealed the changing rule of dynamic Diels-Alder bond molecular structures with temperature. The DCPNs possess controllable tensile properties including superior ductility and certain rigidity via adjusting fatty chain component, which is in accordance with the result of dynamic mechanical analysis. Thermal gravimetric analysis demonstrated the DCPNs had excellent thermostability, and the main peak decomposition temperatures were all above 460 degrees C. The nature of the dynamic Diels-Alder bonds could make shattered DCPNs be reprocessed multiple times under relatively mild conditions. The DCPNs displayed certain shape memory properties, and the shape fixation and recovery ratio at the last two cycles were kept above 95.53% and 84.58%, respectively. This work will help with the development on this kind of bio-based polymers containing dynamic Diels-Alder covalent bonds.