Dynamics of disordered diblocks of polyisoprene and polyvinylethylene

B. H. Arendt, R. Krishnamoorti, R. M. Kannan, K. Seitz, J. A. Kornfield, J. Roovers

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


The apparent thermorheological simplicity of disordered diblocks is reconciled with the failure of time-temperature superposition of corresponding miscible blends by examining the relaxation of the constituent blocks using rheo-optical techniques. Diblocks of 1,4-polyisoprene (PIP) and polyvinylethylene (PVE) are examined over a range of temperatures for two compositions (φPIP = 0.25 and 0.75). Unlike blends of PIP and PVE, the block copolymers appear to obey time-temperature superposition on the basis of their viscoelastic properties. However, departure from thermorheological simplicity is exposed in their stress-optical behavior. In particular, the copolymer rich in the high Tg component (φPIP = 0.25) shows distinct temperature dependencies for the individual blocks, in accord with the behavior of PIP/PVE blends. The block copolymer rich in the low Tg component (φPIP = 0.75) is thermorheologically simple because both blocks have similar monomeric friction coefficients ζo,PVE ≈ ζo,PIP, again in accord with prior results on PIP/PVE blends. The failure of time-temperature superposition in these diblocks was not previously observed because the change in ζo,PVEo,PIP with temperature produces subtle changes in the overall relaxation spectrum relative to a linear chain of uniform friction.

Original languageEnglish (US)
Pages (from-to)1138-1145
Number of pages8
Issue number4
StatePublished - Feb 24 1997
Externally publishedYes

ASJC Scopus subject areas

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


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