caa a22 4500 605466971 CHVBK 20210128100309.0 cr unu---uuuuu 210128e20151001xx s 000 0 eng 10.1007/s00397-015-0876-5 doi (NATIONALLICENCE)springer-10.1007/s00397-015-0876-5 Startup shear of a highly entangled polystyrene solution deep into the nonlinear viscoelastic regime [Elektronische Daten] [Yanfei Li, Gregory McKenna] We have employed optical particle tracking velocimetry to directly visualize the deformation field of a highly entangled polystyrene/diethyl phthalate (PS/DEP) solution (entanglement density Z = 61) in a parallel plate geometry. To probe the existence of shear banding, startup shear tests were carried out deep into the nonlinear viscoelastic (NLVE) regime. By roughening the surface of the rheometer plates, wall slip was effectively suppressed. In the presence of edge fracture and prior to it, steady-state shear banding was not seen as evidenced by velocity profiles that were linear for most of the shear tests. An exception was for an extremely high Weissenberg number Wi = 255, for which weak transient banding was observed. For the PS/DEP system studied, the results suggest that in the absence of wall slip, shear banding is not a steady-state phenomenon and weak shear banding is observed only in the transient state and this could possibly correlate with the edge fracture effects. Springer-Verlag Berlin Heidelberg, 2015 Melt flow instability nationallicence Edge fracture nationallicence Shear banding nationallicence Nonlinear rheology nationallicence Wall slip nationallicence Entangled polymer nationallicence Li Yanfei Department of Chemical Engineering, Edward E. Whitacre, Jr. College of Engineering, Texas Tech University, 79409, Lubbock, TX, USA aut McKenna Gregory Department of Chemical Engineering, Edward E. Whitacre, Jr. College of Engineering, Texas Tech University, 79409, Lubbock, TX, USA aut Rheologica Acta Springer Berlin Heidelberg 54/9-10(2015-10-01), 771-777 0035-4511 54:9-10<771 2015 54 397 https://doi.org/10.1007/s00397-015-0876-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00397-015-0876-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Li Yanfei Department of Chemical Engineering, Edward E. Whitacre, Jr. College of Engineering, Texas Tech University, 79409, Lubbock, TX, USA aut NATIONALLICENCE 700 1- McKenna Gregory Department of Chemical Engineering, Edward E. Whitacre, Jr. College of Engineering, Texas Tech University, 79409, Lubbock, TX, USA aut NATIONALLICENCE 773 0- Rheologica Acta Springer Berlin Heidelberg 54/9-10(2015-10-01), 771-777 0035-4511 54:9-10<771 2015 54 397