Stress Relaxation in Entangled Polymer Melts

Stress relaxation in entangled polymer melts.

We present an extensive set of simulation results for the stress relaxation in equilibrium and step-strained bead-spring polymer melts. The data allow us to explore the chain dynamics and the shear relaxation modulus, G(t), into the plateau regime for chains with Z=40 entanglements and into the terminal relaxation regime for Z=10. Using the known (Rouse) mobility of unentangled chains and the m...

Syddansk Universitet 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...

Stress relaxation in unentangled and entangled polymer liquids

We develop a stochastic model for the dynamics of a dense fluid of flexible linear macromolecules. A polymer is represented by a harmonic chain of beads whose mobilities fluctuate in time between two values. A bead in the low-mobility state does not execute local motions, but may move by a cooperative slithering process involving the entire chain. A bead in the high-mobility state may execute b...

Elastic breakup in uniaxial extension of entangled polymer melts.

Five entangled melts, with the number of entanglements per chain ranging from 25 to 160, have been studied to illustrate how cohesive strength can be overcome in either continuous or interrupted extension (i.e., during or after uniaxial stretching). The internal elastic stress due to chain deformation from imposed strain appears to be the cause of the observed yielding behavior that reveals sca...