Stress relaxation in entangled polymer melts.

Stress relaxation in entangled melts of unlinked ring polymers.

Stress relaxation in unlinked ring polymer melts poses an important challenge to our theoretical understanding of entangled polymer dynamics. Recent experiments on entangled unlinked ring melts show power-law stress relaxation with no hint of a rubbery plateau, usually the hallmark of entangled polymers. Here we present a theory for stress relaxation in rings analogous to the successful approac...

Syddansk Universitet Stress Relaxation in Entangled Polymer Melts

Long-lived interchain contacts in polymer melts

We will study time dependence of interchain contacts in entangled and unentangled polymer melts. We find that ‘‘clusters’’ of contacts in entangled melts persist in time up to at least 0.2 of the longest relaxation time. The clusters of contacts in un-entangled melts disappear and reappear on at least two orders of magnitude shorter time scale. We also examine time-dependent correlation functio...

Induced orientational effects in relaxation of polymer melts.

We study stress relaxation in bidisperse entangled polymer solutions. Shorter chains embedded in a majority of longer ones are known to be oriented by coupling to them. We analyze the mechanism for this both by computer simulation and theoretically. We show that the results can be understood in terms of stress fluctuations in a polymer melt and chain screening. Stress fluctuations are frozen on...

Polymer-mode-coupling theory of the slow dynamics of entangled macromolecular fluids

A microscopic statistical dynamical theory of the slow dynamics of entangled macromolecular fluids has been formulated at the level of effective generalized Langevin equations-of-motion of a tagged polymer. A novel macromolecular version of mode-coupling theory is employed to approximately capture the cooperative motions of entangled polymers induced by the long range, self-similiar interchain ...