title: Extensional flow behavior of aqueous guar gum derivative solutions by capillary breakup elongational rheometry (CaBER).
abstract: The extensional rheological properties of aqueous ionic carboxymethyl hydroxypropyl guar gum (CMHPG) and non-ionic hydroxypropyl guar gum (HPG) solutions between the semi-dilute solution state and the concentrated network solution state were investigated by capillary breakup elongational rheometry (CaBER). Carboxymethylated guar gum derivatives show an instable filament formation in deionized water. The ratio of elongational relaxation time λE over the shear relaxation time λS follows a power law of λE/λS∼(c · [η])(-2). The difference of the relaxation times in shear and elongation can be related to the loss of entanglements and superstructures in elongational flows at higher strains.
authors.affiliation: Institute for Technical and Macromolecular Chemistry, University of Hamburg, Bundesstraße 45, 20146 Hamburg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Szopinski
authors.affiliation: Institute of Polymer Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Strasse 1, 21502 Geesthacht, Germany.
authors.forename: Ulrich A
authors.initials: UA
authors.lastname: Handge
authors.affiliation: Institute for Technical and Macromolecular Chemistry, University of Hamburg, Bundesstraße 45, 20146 Hamburg, Germany.
authors.forename: Werner-Michael
authors.initials: WM
authors.lastname: Kulicke
authors.affiliation: Institute of Polymer Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Strasse 1, 21502 Geesthacht, Germany; Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Abetz
authors.affiliation: Institute for Technical and Macromolecular Chemistry, University of Hamburg, Bundesstraße 45, 20146 Hamburg, Germany. Electronic address: luinstra@chemie.uni-hamburg.de.
authors.forename: Gerrit A
authors.initials: GA
authors.lastname: Luinstra
keywords: Capillary breakup elongational rheometry (CaBER); Extensional flow; Guar gum derivatives; Relaxation times