Insight into the Role of Filler Network in the Viscoelasticity of a Carbon Black Filled Thermoplastic Elastomer: A Strain Dependent Electrical Conductivity Study

Abstract

In conventional rheological and mechanical tests, particle‐particle interactions in the filler network are always entangled with polymer‐particle ones, and thus knowledge of their relative role in the viscoelasticity of filled elastomer is still lacking. In this study, a strain‐dependent, electrical conductivity measurement during cyclic deformation was adopted for the first time to elucidate the role of the filler network in the viscoelasticity of filled elastomers, since electrical conductivity only depends on the particle‐particle interactions in the filler network. The results indicate that a percolating carbon black (CB) network is broken down under large strain and can be partly reformed again with the release of the strain. Further, the weakening of particle‐particle interactions dependent on the percolation of the CB network can find its origin in the hystersis and stress softening effects in the mechanical measurements. It is concluded that the mechanical viscoelasticity of filled elastomer is to a large extent related to the filler network rather than to the polymer‐particle interactions.