Yieldlike constitutive transition in shear flow of entangled polymeric fluids.
We describe an unexpected constitutive transition in entangled polymer solutions. At and beyond a critical stress, the initial spatially homogeneous and well-entangled sample transforms from its entangled (coiled) state into a fully disentangled (stretched) state over a period during which the resulting shear rate increases in a spatially inhomogeneous fashion. In the mode of controlled shear rate, the sample exhibits a stress plateau over three decades. Flow birefringence and normal stress observations unravel additional features of these flow phenomena.
Tapadia
Prashant
P
Department of Polymer Science and Maurice Morton Institute of Polymer Science, University of Akron, Akron, OH 44325, USA.
Wang
Shi-Qing
SQ