The effect of Sb2O3/DBDPE ratio on the flame retardancy and physico-mechanical properties of EPDM elastomer

The flammability of ethylene-propylene-diene terpolymer (EPDM) filled with decabromodiphenylethane (DBDPE) and antimony trioxide (Sb2O3) is investigated. The effects of DBDPE and Sb2O3 on flammability and physico-mechanical properties of EPDM mixture is examined. In order to determine the optimum DBDPE/Sb2O3 ratios in EPDM mixture, the amount of DBDPE and Sb2O3 has been changed while all the other parameters were kept constant. EPDM blends that contains with different amounts of flame retardants mixed in laboratory-mixer and vulcanized in compression type laboratory-press. While rheometer tests were done in semi product step, density, hardness, tensile strength, elongation at break tests have been done to the final product for each formulation. To compare the results limiting oxygen index (LOI) and UL-94 flammability tests, thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used. The best result for flame retardant properties was found for the blend contains 20 phr DBDPE and 10 phr Sb2O and the LOI's of this mixture was found as 25.6. The results showed that flame retardancy is inadequate when DBDPE and Sb2O3 were used alone but combination of DBDPE and Sb2O3 is increased flame retardancy of EPDM. The results showed that increasing content of Sb2O3 in DBDPE/ Sb2O3 improved the flame retardant property and thermal stability of EPDM. While the addition of DBDPE and Sb2O3 flame retardants improved the flame retardation of EPDM, it caused deterioration of tensile strength and elongation at break of EPDM.