One-Pot Sustainable Synthesis of Intrinsically Flame-Retardant Epoxy Vitrimers Using Vitamin B6-Derived Multifunctional Building Block

Flame-retardant vitrimer has effectively addressed the fire risk and recyclability issues of epoxy thermosets, but traditional epoxy vitrimers face separated flame-retardant structures and dynamic bonds as well as complex synthesis relying on scarce materials. Therefore, integrating flame-retardant structures with exchangeable covalent networks via sustainable chemistry is essential. Here, we report a class of intrinsically flame-retardant epoxy vitrimers synthesized via a one-pot sustainable strategy using pyridoxal phosphate (PLP), the naturally abundant active form of vitamin B6, as a multifunctional building block. PLP first reacts with polyetheramine D230 via a controlled Schiff-base reaction to generate dynamic curing agents, which subsequently cross-link with epoxy monomer to form covalent adaptive networks. The optimized epoxy vitrimer (EP-0.5) exhibits an activation energy of 124.04 kJ·mol–1 for bond exchange and demonstrates a high glass transition temperature (126.8 °C), robust tensile strength (∼59 MPa), markedly enhanced self-healing ability (∼100% crack healing), and solvent resistance. Notably, it demonstrates significant fire safety improvements with EP-0.5 reaching 25% of the limited oxygen index, reductions of 55.0% in peak heat release rate, 42.3% in smoke production rate, and 59.2% in CO2 emissions relative to the control sample. Overall, this study presents an easy approach to biomass-derived epoxy vitrimers that combine intrinsic flame retardancy and tailored dynamic features, providing a promising basis for sustainable high-performance thermoset polymers.