Inorganic-organic dual modification of magnesium borate whisker by magnesium hydrate and dodecyl dihydrogen phosphate and its effect on the fire safety and mechanical properties of epoxy resin

A novel hybrid of double-modified magnesium borate whisker was synthesized to enhance the fire safety and mechanical characteristics of epoxy resin (EP). First, magnesium hydroxide (MH) was grown on the surface of the magnesium borate whisker (MBW) using an in-situ growth technique. Second, dodecyl dihydrogen phosphate (DDP) was grafted onto the surface of MH-coated MBW to synthesize an inorganic–organic hybrid (MBW@MH-DDP). The structure, morphology, and composition of MBW@MH-DDP were characterized utilizing XRD, SEM, FTIR, and measurement of water contact angle. The inorganic–organic hybrid, MBW@MH-DDP, having a hydrophobic surface was synthesized successfully. Subsequently, the synthesized MBW@MH-DDP was incorporated into EP and its fire properties and mechanical properties were assessed. The results showed that the PHRR, PSPR, THR, and TSP of the EP composite with MBW@MH -DDP were substantially lowered. Additionally, the LOI and char yield of the EP composite increased dramatically. The mechanism underlying enhancing smoke suppression and flame retardancy of EP composite with MBW@MH-DDP was examined by analyzing the corresponding residue char. In particular, the incorporation of MBW@MH-DDP did not deteriorate the mechanical properties of EP, but slightly improved it. The findings provided a novel strategy for MBW modification to boost the fire safety and mechanical characteristics of EP.