Constitutive model that shows extension thickening for entangled solutions and extension thinning for melts

From melt to solution: Scaling relations for concentrated polystyrene solutions

“…The experimental data discussed correspond to those presented by Bhattacharjee et al (2002) and Acharya et al (2008), and are taken from Desai and Larson (2014). The polymers used were nearly monodisperse PSs with molar masses of 1950 kg=mol and 3900 kg=mol, denoted as PS-1950 andPS-3900, respectively.…”

“…Moreover, DEP was also utilized in polymer solutions with polymer concentrations ranging from marginally entangled to highly entangled in order to quantify the effect of entanglement density on the dynamics in nonlinear step shear relaxation measurements [Archer (1999); Islam et al (2001); Archer and Sanchez-Reyes (2002); Sanchez-Reyes and ]. The steady-state uniaxial extensional viscosities of highly entangled polymer solutions were reported by Bhattacharjee et al (2002), Acharya et al (2008), and Sridhar et al (2014), and the data were modeled in the framework of the Mead, Larson, and Doi model and its modifications [Bhattacharjee et al (2002); Desai and Larson (2014)], or by use of a double constraint release model including chain stretch [Bhattacharjee et al (2003)]. …”

Stress relaxation following uniaxial extension of polystyrene melt and oligomer dilutions

“…Recently it seems that several quantitative ideas are capable of predicting the dynamics of these entangled solutions, oligomer dilutions and pure melts [11,17,18,19,20,21]. However, in the evaluation of theoretical ideas, it is important that the startup and steady extensions are supplemented with additional extensional measurements.…”

A non-Newtonian fluid model with an objective vorticity

“…This is caused by the finite stretch of individual chains so that chain disentanglement or slippage occurs at high flow stresses. In viscoelastic models, a ceiling stretch is often incorporated to address this finite extensibility, as seen both in dumbbell-type models [16,17] and in tube models [18]. A similar idea is adopted here by introducing a ceiling stretch S 0 and modifying the actual stretch of the polymer coil as…”