Comparison of Mullins Effect Anisotropy of the Elastomers Reinforced by Carbon-Black and Silica Filler

Anisotropy of the internal damage caused by imposed deformation, which is called stress-softening or Mullins effect, was investigated for a carbon-black (CB) filled styrene butadiene rubber (SBR/CB) sequence two tensile measurements. A wide-width pristine sheet specimen satisfying pure shear (planar) stretching geometry first subjected to single loading-unloading cycle with maximum stretch (λm). The rectangular subsamples were cut out from unloaded and relaxed such that long axis had an angle θ = 0° 90° relative pre-stretching axis. Subsequently, uniaxial conducted, (D0 D90) at each evaluated as function λm difference in stress-strain data between samples. Almost no anisotropy (f D0/D90 ≈ 1) observed moderate regime < 3. This contrast large 3) corresponding previously reported silica SBR silane coupling agent (SBR/Silica). f values SBR/CB high > 3 increased became comparable those SBR/Silica. significantly SBR/Silica reflects differences types destructed molecular bonding filler networks filler/rubber interfaces elastomers.