Miscible polyisoprene/polystyrene blends: Distinct segmental dynamics but homogeneous terminal dynamics

Yiyong He, T. R. Lutz, M. D. Ediger*, Marines Pitsikalis, Nikolaos Hadjichristidis, Ernst D. Von Meerwall

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

The segmental and terminal dynamics of the individual components in miscible blends of polyisoprene (PI) and polystyrene (d 3PS) were characterized over a wide temperature range. Though the system has a large positive Flory-Huggins interaction parameter Χ ∼ 0.1, it is miscible in the temperature range of study due to low molecular weight. 13C and 2H NMR relaxation measurements were performed to extract the segmental relaxation times. Pulse-gradient spin-echo NMR was used to determine the center-of-mass diffusion coefficients. Though the segmental dynamics of PI and PS components differ by more than 2 decades at T g + 50 K in the blends, their terminal dynamics (in terms of monomeric friction coefficients) are essentially identical. We know of no other system with this behavior. The distinct component segmental dynamics can be reasonably interpreted by the Lodge/McLeish model. The unusual homogeneous terminal dynamics may be due to a large thermodynamic barrier to diffusion in this system. The monomeric friction coefficients are well reproduced by the Gordon-Taylor mixing rule.

Original languageEnglish (US)
Pages (from-to)6216-6226
Number of pages11
JournalMacromolecules
Volume38
Issue number14
DOIs
StatePublished - Jul 12 2005

ASJC Scopus subject areas

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

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