Synthesis, comprehensive characterization and comparative flame retardancy analysis of three metal-organic frameworks incorporated into epoxy resin

Abstract

Epoxy resin (EP), a prevalent thermoset material, is renowned for its exceptional corrosion resistance, thermal stability, and mechanical properties. However, its high flammability and toxic smoke emission pose significant concerns, necessitating the enhancement of its flame retardancy. Metal-organic frameworks (MOFs), with their reticulated structures and porous characteristics, exhibit superior thermal insulation and adsorption properties. Through comparative experiments, we aim to optimize MOF flame retardant formulations to bolster the flame resistance of EP and then enhance its fire safety. In this work, Cu-MOF, Fe-MOF, and Co-MOF were successfully synthesized at room temperature for meeting the requirements of intrinsic safety and then incorporated into EP at a 5 wt% loading to create advanced EP/MOFs composites. The investigation revealed that all three MOFs effectively elevated the limiting oxygen index and reduced smoke density rating of EP. Notably, EP/Co-MOF stood out in suppressing smoke and heat release, with reductions of 40.5 % in peak specific heat release rate (PSPR), 26.4 % in total smoke production (TSP), and 44.4 % in peak heat release rate (pHRR) compared to EP. Furthermore, EP/Co-MOF demonstrated superior compatibility compared to EP/Cu-MOF and EP/Fe-MOF, mitigating mechanical degradation. Consequently, Co-MOF emerges as a promising flame retardant and smoke suppressant for EP, showcasing significant application potential.