Paper Number
PM18
Session
Polymer Melts: From Molecular Rheology to Processing
Title
Attempts to coarse grain a slip-link model to a tube model
Presentation Date and Time
October 17, 2018 (Wednesday) 11:30
Track / Room
Track 2 / Plaza I
Authors
- Taletskiy, Konstantin (Illinois Institute of Technology, Chemical and Biological Engineering)
- Schieber, Jay D. (Illinois Institute of Technology, Chemical Engineering)
Author and Affiliation Lines
Konstantin Taletskiy and Jay D. Schieber
Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL 60616
Speaker / Presenter
Taletskiy, Konstantin
Text of Abstract
A recent comparison between experiments and theories for the dynamic modulus of linear/star-branched entangled polymer blends revealed that tube models were unable to describe simultaneously two different sets of data. Both the branch-on-branch (BoB) computer algorithm, and the hierarchical model were used with various sets of parameter values. While one set of values could describe one data set, it failed to describe the other. On the other hand, the discrete slip-link model (DSM) was able to describe both sets simultaneously, using parameters determined for monodisperse linear chains only. Since the slip-link level of description of entanglements is more detailed than that for tubes, it is computationally more expensive. Therefore, it might be useful to explore whether tube models can be repaired with information gleaned from slip-link models. Or, put another way, can slip-links be further coarse grained to develop a tube model that agrees with the experiment? Here we present evidence that tube models and slip-link models are not compatible. First, we show that they predict different scaling of the longest relaxation time of star-branched chains with and without constraint dynamics. Furthermore, coarse graining of the DSM to create a modified tube description fails to reproduce the longest relaxation time scaling of the detailed model. Repair of the tube model does not seem possible.