Extension induced phase separation and crystallization in semidilute solutions of ultra high molecular weight polyethylene

Sara Lindeblad Wingstrand, Luna Imperiali, Roman Stepanyan, Ole Hassager*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

47 Downloads (Pure)

Abstract

Abstract We investigate the influence of controlled uniaxial extension on various flow induced phenomena in semidilute solutions of ultra high molecular weight polyethylene (UHMwPE). Concentrations range from 9 w% to 29 w% and the choice of solvent is paraffin oil (PO). The start-up extensional behavior is measured at various Hencky strain rates ε ˙ and at two different temperatures ( 150 ∘ C and 170 ∘ C ) well above the melting point. At ε > 0.9 the qualitative behavior of the samples differ significantly depending on the imposed conditions and the concentration of the samples. Overall we propose two flow scenarios: Scenario 1 - flow induced phase separation resulting in an unstable bulky filament and Scenario 2 - flow induced phase separation and crystallization resulting in a stable deformation and a smooth strongly strain hardening filament. Scenario 2 is observed only at 150 ∘ C at high ε ˙ and high concentrations. Scenario 1, observed at both temperatures, is most pronounced at low rates and/or high concentrations.
Original languageEnglish
JournalPolymer
Volume136
Pages (from-to)215-223
ISSN0032-3861
DOIs
Publication statusPublished - 2018

Keywords

  • Crystallization
  • Extensional flow
  • Rheology

Cite this