Hybrid Reinforcement of EPDM Composites Using Carbon Black and Aramid Fibers for Enhanced Mechanical Performance

Ethylene-propylene-diene monomer (EPDM) rubber is widely used in sealing and vibration-control applications because of its excellent thermal and weather resistance. However, achieving simultaneous improvement in stiffness and toughness remains challenging due to its nonpolar nature and limited interfacial interactions with reinforcing fillers. In this study, carbon black (CB) and aramid fiber (AF) are employed as complementary reinforcements for EPDM composites. CB is expected to enhance stiffness through filler network formation, whereas AF may improve toughness and tear resistance through crack-bridging and energy-dissipation mechanisms. EPDM composites containing CB or AF alone will first be prepared to identify the individual reinforcement effects, followed by the fabrication of CB/AF hybrid-filled composites. Vinyltriethoxysilane (VTES) treatment will be applied to improve interfacial interactions between AF and the EPDM matrix. The effects of AF content, VTES treatment, and CB/AF hybridization on the mechanical properties of EPDM composites will be systematically investigated. In addition, high-shear fibrillation of AF will be explored to produce micro- or nanoscale fibers and evaluate the influence of fiber size on dispersion and reinforcement efficiency. This study aims to provide an effective strategy for improving the mechanical performance of EPDM composites through hybrid filler design and interfacial engineering.