THE PAYNE EFFECT: PRIMARILY POLYMER-RELATED OR FILLER-RELATED PHENOMENON?

摘要

About 10% of vehicle fuel energy is wasted to overcome the rolling resistance of tires,and the viscoelastic energy losses from the rubber compounds in tires are a major source of rolling resistance.The related hysteretic softening behavior at small dynamic strains(Fletcher-Gent effect or Payne effect)was studied as a function of particle size,filler volume fraction,and temperature for carbon black(CB)-reinforced styrene-butadiene rubber(SBR)and a paste-like material composed of CB-filled paraffin oil.Similarities and differences between the Payne effect responses for high molecular weight polymer versus low molecular weight liquid in these simple composites provided insights into the relative contributions of filler networking and polymer-related effects.The low strain limit for dynamic storage modulus was found to be remarkably similar for CB-filled oil compared to CB-filled SBR,in agreement with pioneering work by Payne and his coworkers.This provides clear evidence that the deformation-induced breaking(unjamming)of the filler network-characterized by direct filler-filler contacts that are percolated throughout the material-is the main cause for the Payne effect.However,the polymer matrix does play a secondary role as demonstrated by a reduction in Payne effect magnitude with increasing temperature for the CB-reinforced rubber,which was not observed to a significant extent for the oil-CB system.