Packing length influence in linear polymer melts on the entanglement, critical, and reptation molecular weights

Lewis J. Fetters, David J. Lohse, Scott Thomas Milner, William W. Graessley

Research output: Contribution to journalArticle

318 Citations (Scopus)

Abstract

We have shown in previous studies that the entanglement molecular weight for a polymer melt, Me, is related by a power law to p, the packing length of the polymer species. We now find that power laws also describe the molecular weights characterizing the melt viscosity, Mc marking the onset of entanglement effects and Mr the crossover to the reptation form. The packing length exponents for Me, Mc, and Mr differ significantly, however. The long-held notion that the ratio Mc/Me has the same value for all species is therefore incorrect. Further, the observed and predicted values of Mr for two species, 1,4-polybutadiene and polyisobutylene, have been found to agree, within the uncertainties, with the projected values. Finally, the variations with packing length are such that all three characteristic molecular weights would appear to converge on the same value near p = 9 angstroms. As yet, no species with such a large packing length has been completely studied rheologically. But the range is not outlandish and is clearly reachable by appropriate synthetic methods.

Original languageEnglish (US)
Pages (from-to)6847-6851
Number of pages5
JournalMacromolecules
Volume32
Issue number20
DOIs
StatePublished - Oct 5 1999

Fingerprint

Polymer melts
Molecular weight
Polybutadienes
Polymers
Viscosity

All Science Journal Classification (ASJC) codes

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

Cite this

Fetters, Lewis J. ; Lohse, David J. ; Milner, Scott Thomas ; Graessley, William W. / Packing length influence in linear polymer melts on the entanglement, critical, and reptation molecular weights. In: Macromolecules. 1999 ; Vol. 32, No. 20. pp. 6847-6851.
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Packing length influence in linear polymer melts on the entanglement, critical, and reptation molecular weights. / Fetters, Lewis J.; Lohse, David J.; Milner, Scott Thomas; Graessley, William W.

In: Macromolecules, Vol. 32, No. 20, 05.10.1999, p. 6847-6851.

Research output: Contribution to journalArticle

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