Rheology of Polydisperse Star Polymer Melts: Extension of the parameter-free tube model of Milner and McLeish to arbitrary arm-length polydispersity

J.J.M. Slot, Paul A.M. Steeman

    Research output: Contribution to journalArticleAcademicpeer-review

    3 Citations (Scopus)


    This paper considers the extension of the parameter-free tube model of Milner and McLeish for stress relaxation in melts of monodisperse star polymers to star polymers whose arms have a continuous molecular weight distribution such as the Flory distribution in the case of star-nylons and star-polyesters. Exact expressions are derived for the relaxation spectrum and the relaxation modulus for star polymers having an arbitrary continuous arm-length distribution. For a Flory distribution a comparison is made with results of dynamic measurements on a melt of 8-arm poly(-caprolactone) (PCL) stars. An excellent quantitative agreement over a large frequency range is found, however, only if one treats, in contrast with the original parameter-free tube model approach, the entanglement molecular weight that determines the relaxation spectrum as a fitting parameter independent of the entanglement molecular weight of the linear PCL. This discrepancy is not in anyway related to the polydispersity in arm-length, but a consequence of the thermorheological complexity of the PCL stars. A similar discrepancy has been observed for hydrogenated polybutadiene stars, as described by Levine and Milner.
    Original languageUndefined
    Pages (from-to)387-399
    Number of pages13
    JournalMacromolecular theory and simulations
    Issue number6
    Publication statusPublished - 2005


    • Melt
    • Rheology
    • Polycaprolactone
    • Theory
    • star polymers
    • METIS-231031
    • IR-72013

    Cite this