Enhanced flame-retardant and mechanical properties of epoxy resin by combination with layered double hydroxide, Mg2B2O5 whisker, and dodecyl dihydrogen phosphate

•The functionalized layered double hydroxide (LDH) was fabricated following the double modification.•The functionalized LDH improved the fire safety and mechanical properties of epoxy resin simultaneously.•Incorporation of the functionalized LDH provided a stable and compact char layer.•The interfacial combination between LDH coated Mg2B2O5 whisker and epoxy resin was enhanced by dodecyl dihydrogen phosphate grafting.