Molecular physics of a polymer engineering instability: Experiments and computation

Hassell D. G., Mackley M. R., Sahin M., Wilson H. J., Harlen O. G., McLeish T. C. B.

PHYSICAL REVIEW E, cilt.77, sa.5, 2008 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 77 Sayı: 5
  • Basım Tarihi: 2008
  • Doi Numarası: 10.1103/physreve.77.050801
  • Dergi Adı: PHYSICAL REVIEW E
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • İstanbul Teknik Üniversitesi Adresli: Hayır

Özet

Entangled polymer melts exhibit a variety of flow instabilities that limit production rates in industrial applications. We present both experimental and computational findings, using flow of monodisperse linear polystyrenes in a contraction-expansion geometry, which illustrate the formation and development of one such flow instability. This viscoelastic disturbance is observed at the slit outlet and subsequently produces large-scale fluid motions upstream. A numerical linear stability study using the molecular structure based Rolie-Poly model confirms the instability and identifies important parameters within the model, which gives physical insight into the underlying mechanism. Chain stretch was found to play a critical role in the instability mechanism, which partially explains the effectiveness of introducing a low-molecular weight tail into a polymer blend to increase its processability.