Natural coal-derived graphite as rubber filler and the influence of its progressive graphitization on reinforcement performance

Abstract

This study introduces a reinforcing rubber filler, natural coal-derived graphite (NCDG), evaluating how its progressive structural evolution from meta-anthracite (MA), semi-graphite (SG) to cryptocrystalline graphite (CG) during the natural graphitization process affects their reinforcing performance to styrene-butadiene rubber (SBR) composites. The highly graphitized NCDG fillers exhibit good filler dispersion, more bound rubber content, and well compatibility between filler and rubber matrix when compounded with SBR, and significantly enhance the mechanical properties of SBR composite (tensile strength can reach 22.8 MPa), as well as improving the storage modulus, wet-skid resistance, wear resistance, and electrical conductivity. The formation of microcrystalline multilayer graphene and graphene nanoplatelets exfoliated by mechanical shear stress during ball grinding and rubber compound mixing plays an important role in improving the reinforcement performance of rubber composites. This research provides valuable insights into the utilization of NCDG as a cost-effective and environment-friendly reinforcing filler for rubber composites.