Comparison of dynamic shear properties of styrene-butadiene vulcanizates filled with carbon black or polymeric fillers

The dynamic shear behavior of SBR 1500 vulcanizates filled with polymeric f illers of 24.6, 40.2, and 74.7 nm diameter and various filler loading up to 100 phr (parts per 100 parts of rubber), and its dependence of strain ampl itude up to 14%, have been investigated. The results are compared with carb on-black-filled vulcanizates. The reinforcement ability of polymeric filler s is comparable to that of carbon black, depending on filler particle diame ter. As expected, the smaller particles have a higher reinforcement effect than larger particles. The Payne effect, that is, the decrease of storage s hear modulus G' with increasing strain amplitude and the appearance of a lo ss modulus G " maximum at strains of a few percent, has also been observed in vulcanizates with polymeric fillers. The loss modulus maximum of vulcani zates filled with polymeric fillers is at higher strain amplitudes and is l ess pronounced than for carbon-black-filled vulcanizates. The results are d iscussed shortly in terms of recent models based on the idea of filler netw orking within the rubbery matrix. The experimental G' data are adjusted wit h the deagglomeration-reagglomeration Kraus model (1984). (C) 1999 John Wil ey & Sons, Inc.