New Light on Old Wisdoms on Molten Polymers: Conformation, Slippage and Shear Banding in Sheared Entangled and Unentangled Melts
Year: 2009
Type: article
Abstract: The flow of viscoelastic materials is usually interpreted as resulting from intramolecular properties. Typically, the non-linear flow behaviour and sluggish relaxation dynamics in entangled polymers are interpreted by a disentanglement process. This molecular interpretation has never been validated by direct observation. We report here on in situ observations of polymer melts under steady-state shear flow using neutron scattering and particle tracking velocimetry. It is shown that the chains remain largely undeformed under steady-state shear flow whereas wall slippage and shear-banding are identified in both entangled and unentangled polymer melts. These observations are of prime importance; they reveal that the flow mechanism and its viscoelastic signature reflect a collective effect and not properties of individual chains.
Institutions: Centre National de la Recherche Scientifique, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, CEA Paris-Saclay - Etablissement de Saclay, Laboratoire Léon Brillouin, CEA Paris-Saclay, Université Joseph Fourier, CEA Grenoble, Structure et Propriétés d'Architectures Moléculaires, Systèmes Moléculaires et nanoMatériaux pour l'Énergie et la Santé
Language: English
Subfield: Fluid Flow and Transfer Processes
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2017179508