EPDM with Biochar, Carbon Black, Aramid Pulp and Ionic Liquid-compatibilized Aramid Pulp

Carbon black (CB) is a fossil fuel-derived product widely used as reinforcement in the rubber industry despite its pollution potential and its high energy-demanding production. Biochar, on the other hand, is a renewable source of carbon recently studied for the partial substitution of CB in elastomeric materials. Aramid pulp/fibers have also been used in a variety of applications in this sector, usually after a surface treatment. In this work, the use of aramid pulp (AP) and biochar in the preparation of ethylene propylene diene monomer (EPDM) composites and hybrid composites has been studied. The 1-n-butyl-3-methylimidazolium methanesulfonate ionic liquid (IL) was used as compatibilizer in AP, and the rubber-filler interaction was studied via thermal, rheometric, mechanical, and swelling analyses. The biochar-EPDM and the reference CB-EDPM compounds showed similar hardness, modulus at 50 % strain and tear strength results. Among the tested fillers, AP was identified as the most effective to obtain EPDM composites with enhanced properties. A synergistic effect of biochar and IL-treated AP was found, resulting in higher tensile strength for the hybrid formulation (EPDM/Bio05AP05IL) compared to those with just biochar or CB, and reasonable strain at break. In all, the hybrid composites of EPDM reinforced with biochar and AP showed the potential to partially or fully replace CB formulations.