The effect of coupling agents on silicate-based nanofillers/carbon black dual filler systems on the properties of a natural rubber/butadiene rubber compound

Nanofillers have been introduced a few years ago, but their application in elastomers is still a challenge. With the existing rubber processing equipment and constraints of rubber mixing, dispersion of nanofillers is difficult. The processability and performance of compounds containing plate- or tube-like silicates in a blend with conventional fillers, such as carbon black (CB), are investigated, and the effect of surface modification of the nanofillers is studied. Processing is facilitated by the replacement of CB by the nanofillers, but curing efficiency is reduced. The dispersion of the fillers is improved with the addition of nanofillers. The dynamic properties of the cured composite material are affected, giving the composite material lower hysteresis, while the mechanical properties are merely affected by the addition of nanofillers. Additionally, the filler–polymer interaction is increased. The addition of a compatibilizing and coupling agent, a silane, has only a minor effect and does not improve processing and properties significantly for these combined filler systems.