A comparison between the effects of sepiolite and silica on mechanical properties and thermal stability of NR/EPDM blend

Abstract

This study focused on improving the ablation properties and mechanical properties of natural rubber (NR)/ethylene propylene diene monomer (EPDM) blends by using two different commercial fillers: sepiolite and silica. The results showed that sepiolite and silica similarly improved both properties in the loading range of interest (0-12.5 phr). However, sepiolite was superior than silica as using less loading to acheive comparable mechanical and thermal properties. The optimum loading of sepiolite was 5 phr, while that of silica was 10 phr. For both filler systems, the minimum ablation rate found was approximately 0.17 mm/s, and the tensile strength and the hardness of corresponding NR/EPDM composite were improved after modification with sepiolite or silica.Thus, the composite reinforced with sepiolite or silica is suitable for many applications, such as internal insulations of rocket motor.