Silicon-Bridged Epoxy Vitrimers with Antibacterial and UV-Blocking Properties

Thedevelopment of multifunctional epoxy resins that can be degradableand reprocessed is of great significance for the conservation of non-renewableresources and environmental protection. Herein, curing agents basedon nitrogen-silicone Schiff base (BOB) and silica-bridged epoxyresin (ETOD) were designed and successfully synthesized. Then, ETODwas cured using BOB to fabricate a multi-silicon-bridge epoxy vitrimercontaining dynamic imine bonds (BOB/ETOD). Notably, because of thepresence of a large number of siloxane chain segments, BOB/ETOD exhibitedexcellent flame retardancy (the peak heat release rate (pHRR) was57.7% lower than that of conventional epoxy resin (DDM/EP) and a carbonresidual rate (RC700) of 27.7%, which is 1.6 times higherthan that of DDM/EP). Furthermore, the networks of BOB/ETOD couldtopologically rearrange due to the reversible exchange reaction ofimine bonds, making them degradable and reprocessable. Surprisingly,BOB/ETOD also had excellent antimicrobial (the antimicrobial ratewas up to 93%) and UV-blocking properties. This work provides a simpleand effective solution for the development of multifunctional epoxy-basedvitrimers, which is conducive to further expanding the applicationfield of epoxy resins.

Automated summary

In this study, curing agents based on nitrogen-silicone Schiff base (BOB) and silica-bridged epoxy resin (ETOD) were synthesized. The cured ETOD using BOB resulted in a multi-silicon-bridge epoxy vitrimer containing dynamic imine bonds (BOB/ETOD). BOB/ETOD showed outstanding flame retardancy, degradability, reprocessability, antimicrobial activity, and UV-blocking properties.