Synergistic effect of an aromatic boronic acid derivative and magnesium hydroxide on the flame retardancy of epoxy resin

To develop new organic/inorganic flame retardants, the aromatic boronic acid derivative 2,4,6-tris(4-boronic-2-thiophene)-1,3,5-triazine (3TT-3BA) and magnesium hydroxide (MH) were selected. The two compounds were added to epoxy resin (EP) to investigate the flame retardant properties and mechanism. The mechanical, thermal, and flame retardant properties of the EP and flame retardant EP were investigated. The morphology of char was characterized by scanning electron microscopy. The results show that mixing EP with both 3TT-3BA and MH results in better thermal stability and flame retardant properties than mixing with only one of the compounds, indicating the synergistic effect of the two components. The elements in the char were investigated by elemental analysis to further investigate the flame retardant mechanism. The result of impact strengths shows that 3TT-3BA can inhibit combustion with MH effectively without decreasing the mechanical strength.