Insights into the Payne Effect of Carbon Black Filled Styrene-butadiene Rubber Compounds

As a widely used reinforcing filler of rubber, carbon black (CB) often enhances the nonlinear Payne effect and its mechanism still remains controversial. We adopt simultaneous measurement of rheological and electrical behaviors for styrene-butadiene rubber (SBR)/CB compounds and CB gel (CBG) during large deformation/recovery to investigate the contribution of conductive CB network evolution to the Payne effect of the compounds. In the highly filled compounds, the frequency dependence of their strain softening behavior is much more remarkable than that of their CB network breakdown during loading, while during unloading the unrecoverable filler network hardly affects the complete recovery of modulus, both revealing that their Payne effect should be dominated by the disentanglement of SBR matrix. Furthermore, the bound rubber adjacent to CB particles can accelerate the reconstruction of continuous CB network and improve the reversibility of Payne effect. This may provide new insights into the effect of filler network, bound rubber, and free rubber on the Payne effect of CB filled SBR compounds.