EPDM Matrix Heat Shielding Materials Based on Boron Containing Fillers as Char Promoters

Due to the low density and insulation capability, EPDM rubber, reinforced with aramid or phenolic fibers, represents the state of the art of Elastomerie Heat Shielding Materials (EFISMS). However, these composites, used as ablatives, tend to exhibit a limited ablation resistance especially in severe hyperthermal environments such as the combustion chamber of rocket motors: here the propellant combustion byproducts cause the thermo-oxidation and mechanical erosion of the ablatives used as protection of the rocket case. In order to increase char retention, the thermooxidation resistance and insulation capabilities, boron based fillers can be added in the material formulation. In this work the effect of three different boron containing fillers embedded in EPDM/phenolic pulp composites was evaluated.