Relaxation behavior of polymer blends after the cessation of shear

L. Kielhorn, R. H. Colby, C. C. Han

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

We investigated the relaxation of a binary polybutadiene/polyisoprene blend after the cessation of steady-state shear using both in situ optical microscopy (OM) and light scattering (LS). Through fast Fourier transforms of the micrographs, we were able to directly relate our LS patterns with the real space morphology. In the steady state we observed ellipsoidal domains and strings. Upon the cessation of shear, these morphologies relaxed to the equilibrium morphology via a variety of mechanisms. After low shear rates were applied, coalescence between domains of random spatial distribution occurred. If the shear rate previously applied was sufficiently high, the strings were found to break up into small droplets forming necklace-like structures. The nonrandom spatial distribution created by shearing resulted in a long-lasting anisotropy at rest. If the previously applied shear rate was further increased, thermodynamic effects became important and anisotropies relaxed very fast as a consequence. A spinodal pattern in both real space and in the LS patterns was found to occur during the relaxation process.

Original languageEnglish (US)
Pages (from-to)2486-2496
Number of pages11
JournalMacromolecules
Volume33
Issue number7
DOIs
StatePublished - Apr 4 2000

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Polymer blends
Light scattering
Shear deformation
Spatial distribution
Anisotropy
Polyisoprenes
Polybutadienes
Relaxation processes
Coalescence
Shearing
Fast Fourier transforms
Optical microscopy
Thermodynamics

All Science Journal Classification (ASJC) codes

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

Cite this

Kielhorn, L. ; Colby, R. H. ; Han, C. C. / Relaxation behavior of polymer blends after the cessation of shear. In: Macromolecules. 2000 ; Vol. 33, No. 7. pp. 2486-2496.
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Relaxation behavior of polymer blends after the cessation of shear. / Kielhorn, L.; Colby, R. H.; Han, C. C.

In: Macromolecules, Vol. 33, No. 7, 04.04.2000, p. 2486-2496.

Research output: Contribution to journalArticle

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