We have studied stress overshoot behavior in startup shear of four monodisperse polymer melts with a range of chain entanglement from Z = 24 to 160 entanglement points per chain. In the elastic deformation regime defined by (gamma)over dot tau(R) > 1 where tau(R) is the Rouse relaxation time, (i) the peak shear stress sigma(max) scales with the time t(max) at the peak to -1/2 power, in contrast to an exponent of -1/4 in the viscoelastic regime (for (gamma)over dot tau(R) < 1), (ii) sigma(max) changes linearly with the elapsed strain at the stress peak gamma(max), which scales with the applied shear rate as (gamma)over dot(1/3), (iii) a supermaster curve collapses time-dependent shear stress growth curves up to the stress maximum at all shear rates for all the four styrene-butadiene rubber samples. (C) 2009 The Society of Rheology. [DOI: 10.1122/1.3086872]
Journal of Rheology
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Copyright 2009 American Institute of Physics. The original published version of this article may be found at http://dx.doi.org/10.1122/1.3086872.
Boukany, Pouyan E.; Wang, Shi-Qing; and Wang, Xiaorong, "Universal Scaling Behavior in Startup Shear of Entangled Linear Polymer Melts" (2009). College of Polymer Science and Polymer Engineering. 104.