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The development of multifunctional epoxy resins that can be degradable and reprocessed is of great significance for the conservation of non-renewable resources and environmental protection. Herein, curing agents based on nitrogen−silicone Schiff base (BOB) and silica-bridged epoxy resin (ETOD) were designed and successfully synthesized. Then, ETOD was cured using BOB to fabricate a multi-silicon-bridge epoxy vitrimer containing dynamic imine bonds (BOB/ETOD). Notably, because of the presence of a large number of siloxane chain segments, BOB/ETOD exhibited excellent flame retardancy (the peak heat release rate (pHRR) was 57.7% lower than that of conventional epoxy resin (DDM/EP) and a carbon residual rate (RC 700 ) of 27.7%, which is 1.6 times higher than that of DDM/EP). Furthermore, the networks of BOB/ ETOD could topologically rearrange due to the reversible exchange reaction of imine bonds, making them degradable and reprocessable. Surprisingly, BOB/ETOD also had excellent antimicrobial (the antimicrobial rate was up to 93%) and UV-blocking properties. This work provides a simple and effective solution for the development of multifunctional epoxy-based vitrimers, which is conducive to further expanding the application field of epoxy resins.

Most epoxy resins (EP) suffer from sacrificial mechanical properties in flame retardancy applications. Through a facile reaction between N‐aminoethylpiperazine (N‐AEP) and 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO), a novel multi‐site interaction flame retardant, DOPO‐based aminoethylpiperazine (abbreviate as AEPO), was successfully synthesized, which could form a ladder‐like cross‐linked network with EP. EP modified by AEPO (EP‐AEPO) was tested for flame retardancy using the limiting oxygen index (LOI), the vertical burning test (UL‐94), and the cone calorimeter test (CCT). According to the results, EP‐10 (EP with 10 phr of AEPO) could pass UL‐94 V‐0 rating and get a LOI value of 35.5%, the peak heat release rate (PHRR) and total heat release (THR) of EP‐10 were also decreased by 25.2% and 29.8%, respectively, which caused by the synergistic charring effect of phosphorus and nitrogen elements contained in the structure of AEPO. Due to the ladder‐like cross‐linked network formed through multi‐site interaction, the mechanical properties demonstrated a significant improved. This work opened up a new strategy for achieving a comprehensive improvement on multifunctional EP through the design of a novel ladder‐like cross‐linked network with multi‐site interaction.

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