The influence of topology and morphology of fillers on the conductivity and mechanical properties of rubber composites

Herein, the comparison of butadiene rubber (BR) composites based on the thermally reduced graphene (TrG), multi-walled carbon nanotubes (MWCNTs) and carbon black (CB) on conductivity and mechanical properties was reported. SEM images of the composites showed that the TrG exhibited better dispersion and compatibility with the BR matrix than that of MWCNTs and CB. Therefore, a significant enhancement of electrical conductivity and mechanical properties of the BR/TrG nanocomposites were obtained at low graphene content. The electrical conductivity of the BR/TrG nanocomposites increased from 1 x 10(-13) S cm(-1) to 1.8 x 10(-4) S cm(-1) in the presence of 7 phr TrG and the electrical percolation threshold was about 4.3 phr, compared with 9.5 phr and 44 phr for MWCNTs and CB, respectively. A 448% improvement of tensile strength and a nearly 2 times improvement of elongation at break were obtained at the graphene content of 7 phr. Compared with the MWCNTs and CB, the content of graphene in composites was much lower than that of MWCNTs and CB when the mechanical properties was similar. The dynamic mechanical properties showed that the TrG efficiently reinforced the storage modulus and reduced the loss factor of the composites relative to MWCNTs and CB. The different reinforcement of TrG, MWCNTs and CB mainly came from the different topology and morphology of the three fillers. Different contact specific area provided different interface interaction, which induced the different dispersity, which influenced the properties of the composites at last.