Crystal nucleation in sheared polymer melts

P. G. Andersen*, Stephen Howard Carr

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

A semiquantitative procedure has been developed for analyzing crystal nucleation in undercooled polymer melts that are undergoing flow. This analysis was applied to the specific ease of molten high density polyethylene experiencing low levels of shearing flow. A custom‐made concentric cylinder viscometer, which could be operated by the Rheometrics mechanical spectrometer instrument, was used to make simultaneous measurements of transmitted torque and optical anisotropy in isothermal melts, The result of the analytical procedure developed here was molecular Size‐dependence of chain distensions caused by prevailing shear. This distribution function was verified by testing against experimentally obtained values of birefringence. Total entropy reduction resulting from this distorted state was then calculated, and the corresponding increase in free energy was found to be at least enough to account for comparable crystal nucleation rates in flowing melts at higher temperatures and in quiescent melts at lower temperatures.

Original languageEnglish (US)
Pages (from-to)215-221
Number of pages7
JournalPolymer Engineering & Science
Volume18
Issue number3
DOIs
StatePublished - Jan 1 1978

ASJC Scopus subject areas

  • Chemistry(all)
  • Polymers and Plastics
  • Materials Chemistry

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