Fabrication of LDH nanosheets on β-FeOOH rods and applications for improving the fire safety of epoxy resin

Layered double hydroxide (LDH) nanosheet-wrapped β-FeOOH rod (LDH-β-FeOOH) hybrids were prepared using a facile method, for the purpose of combining the characteristics of one dimension (1D) and two dimension (2D) to improve the thermal stability and fire resistance of epoxy resin (EP). The hybrids exhibited outstanding dispersion in an EP matrix, with no obvious aggregation. The results of thermogravimetric analysis and cone calorimeter tests indicate that the incorporation of 3% LDH-β-FeOOH hybrids into an EP matrix can significantly improve its thermal stability and fire resistance. Its potential flame retardancy mechanism was investigated by way of the thermogravimetric infrared (TG-IR) technique and X-ray photoelectron spectroscopy. The improvements can be classified into two phases: the condensed-phase and the gas-phase. Nanofillers are transferred to the surface of the matrix, which can not only shield nanocomposites from external radiation and heat feedback from the fire zone, but can also efficiently postpone the transport of oxygen and flammable volatile gases.