Recyclable, biobased, and high-performance poly(amide-imine) vitrimers and the complexes with Co2 + ions

Thermoset polymers are challenging to reprocess and recycle, leading to significant environmental pollution at the end of their life. Incorporating dynamic covalent bonds into cross-linking networks offers an effective solution to these issues. In this study, a partially biobased tris(aldehyde) or tris(vanillin) monomer (TVA) was synthesized through the ring-opening reaction of vanillin with trimethylolpropane triglycidyl ether. Four H 2 N-terminated polyamides with pyridine pendent groups (PY-DAs) were synthesized by polycondensation of a pyridine-containing diester with various diamines. A series of poly(amide-imine) vitrimers with pyridine rings (PYPAIs) were then prepared by reacting TVA with PY-DAs. The incorporation of polyamide segments improved the mechanical properties and thermal stability, whereas the imine bonds provided reprocessability, degradability, and self-healing capabilities. PYPAIs show leading mechanical properties with the tensile strength up to 69.2 MPa to previous reported poly(amide–imine) vitrimers. PYPAI complexes (PYPAIs-Co 2+ ) were formed through coordination with cobalt ions, and the mechanical properties of PYPAIs-Co 2+ were further improved. PYPAIs-Co 2+ exhibited a solvatochromic property in methanol, which may make them used as potential sensor for polar solvents.