APS March Meeting 2017
Volume 62, Number 4
Monday–Friday, March 13–17, 2017;
New Orleans, Louisiana
Session S40: Physics of Ring Polymers
11:15 AM–2:03 PM,
Thursday, March 16, 2017
Room: 387
Sponsoring
Unit:
DPOLY
Chair: Yongmei Wang, University of Memphis
Abstract ID: BAPS.2017.MAR.S40.1
Abstract: S40.00001 : Rheology modification with ring polymers
11:15 AM–11:51 AM
Preview Abstract
Abstract
Author:
Dimitris Vlassopoulos
(FORTH, IESL and University of Crete)
It is now established that experimental unconcatenated ring polymers can be
purified effectively by means of fractionation at the critical condition.
For molecular weights well above the entanglement threshold, purified rings
relax stress via power-law (with an exponent of about -0.4), sharply
departing from their linear counterparts. Experimental results are in
harmony with modeling predictions and simulations. Here, we present results
from recent interdisciplinary efforts and discuss two challenges: (i) the
nonlinear shear rheology of purified ring melts is also very different from
that of unlinked chains. Whereas the latter exhibit features that can be
explained, to a first approach, in the framework in the tube model, the
former behave akin to unentangled chains with finite extensibility and
exhibit much small deformation at steady state. (ii) blends of rings and
linear polymers exhibit unique features in different regimes: The addition
of minute amounts of linear chains drastically affects ring dynamics. This
relates to ring purity and the ability of unlinked linear chains to thread
rings. With the help of simulations, it is possible to rationalize the
observed surprisingly slow viscoelastic relaxation, which is attributed to
ring-linear and ring-ring penetrations. On the other hand, adding small
amounts of rings to linear polymers of different molecular weights
influences their linear and nonlinear rheology in an unprecedented way. The
blend viscosity exceeds that of the slower component (linear) in this
non-interacting mixture, and its dependencies on composition and molecular
weight ratio are examined, whereas the role of molecular architecture is
also addressed. Consequently, closing the ends of a linear chain can serve
as a powerful means for molecular manipulation of its rheology.
This presentation reflects collaborative efforts with S. Costanzo, Z-C. Yan,
R. Pasquino, M. Kaliva, S. Kamble, Y. Jeong, P. Lutz, J. Allgaier, T. Chang,
D. Talikis, V. Mavrantzas and M. Rubinstein.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2017.MAR.S40.1