Component Dynamics in Miscible Blends of 1,4-Polyisoprene and 1,2-Polybutadiene

Jeffrey A. Zawada, Gerald G. Fuller, Ralph H. Colby, Lewis J. Fetters, Jacques Roovers

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61 Scopus citations


The effects of blending on the rheology of the individual components in highly entangled miscible blends of 1,4-polyisoprene (PI) and 1,2-polybutadiene (1,2-PB) are investigated. Blend component contributions to the dynamic modulus, G*(ω), are recovered over the full composition range by complementing dynamic mechanical rheometry with infrared polarimetry. Distinct relaxations for each component are observed. Analysis of the modulus amplitudes of the component G*(ω) contributions reveals that the behavior of the slower relaxing component, 1,2-PB, compares well with constraint release scaling predictions. Each component is found to have a different average number of skeletal bonds between entanglements, in agreement with the predictions of an existing entanglement theory. The components appear to adopt a single reptation tube diameter and a mutual modulus shift factor, bT(T), in each blend. Analysis of the frequency dependence of the component G*(ω) contributions indicates that each component's relaxation is governed by a distinct apparent glass transition temperature, Tg, and that at a constant T -Tg blend composition only mildly influences the component relaxation times. A mild increase in the 1,2-PB relaxation time in the blend suggests a possible increase in the 1,2-PB friction factor in the presence of PI.

Original languageEnglish (US)
Pages (from-to)6861-6870
Number of pages10
Issue number23
StatePublished - Nov 1 1994

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry


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