In-situ coprecipitation formed Fe/Zn-layered double hydroxide/ammonium polyphosphate hybrid material for flame retardant epoxy resin via synergistic catalytic charring

Inspired by the in-situ coprecipitation technology, Fe/Zn-layered double hydroxides (Fe/Zn-LDH) doped ammonium polyphosphate (APP) was prepared for high fire-safety epoxy resins (EP). The investigation on the chemical composition and micromorphology of Fe/Zn-LDH@APP confirmed the uniform deposition of Fe/ZnLDH on the surface of APP. The results showed that EP containing 4 wt% Fe/Zn-LDH@APP exhibited the highest LOI of 29.4% and passed the UL-94 V0 level. Additionally, compared to neat EP, the peak of heat release rate, peak of smoke production rate, and the fire growth rate decreased by 66.4%, 48.4%, and 80.7%. The greatly enhanced flame retardancy of EP was contributed to the highly synergistic charring catalysis via abundant interfacial contact sites. Moreover, the mechanical performance of Fe/Zn-LDH@APP/EPs were slightly affected due to the improved interfacial interaction of Fe/Zn-LDH@APP. Generally, this work exploited a tactful strategy to construct LDH doped APP hybrid material, and presented the potential application in industry.

Automated summary

Inspired by in-situ coprecipitation technology, Fe/Zn-layered double hydroxides (Fe/Zn-LDH) doped ammonium polyphosphate (APP) were prepared for high fire-safety epoxy resins (EP). Fe/Zn-LDH@APP showed uniform deposition on the surface of APP. Results showed that EP containing 4 wt% Fe/Zn-LDH@APP exhibited the highest LOI and passed the UL-94 V0 level. Furthermore, compared to neat EP, the addition of Fe/Zn-LDH@APP decreased the peak of heat release rate, peak of smoke production rate, and the fire growth rate.