Effect of metal oxide supported on active carbon on vulcanization, combustion and thermal ageing properties of flame retardant rubber

With the excellent catalytic synergistic flame retardancy of metal oxide (MO) and its effect of improving the thermal ageing property as well as the porous and large specific surface area characteristic of bamboo based active carbon (AC), a series of metal oxide (Fe₂O₃, CuO, ZnO) supported on active carbon (AC-MO) synergist was prepared by solvent evaporation method. The vulcanization, combustion, thermostability, and thermal ageing properties for synergistic intumescent flame retardant ethylene vinyl-acetate copolymer rubber (EVM) with AC-MO and ammonium polyphosphate/dipentaerythritol was studied. The results showed that AC-MO was the target product and MO dispersed well when supported on AC. AC and AC-MO had a uniform dispersion in the flame retardant EVM. The introduction of AC-MO improved the maximum torque, flame retardancy, and char residue, especially for AC-Fe₂O₃. A Fe₂O₃ supported on AC improved its catalytic charring effect, which improved the integrity and compactness of char residue of flame retardant EVM. As a result, the flame retardancy was improved. After thermal ageing test, the tensile strength of EVM/IFR/AC-MO increased while the elongation at break decreased.