Polymer Entanglements and Nonlinear Viscoelasticity

Entanglements in polymer nanocomposites containing spherical nanoparticles.

We investigate the polymer packing around nanoparticles and polymer/nanoparticle topological constraints (entanglements) in nanocomposites containing spherical nanoparticles in comparison to pure polymer melts using molecular dynamics (MD) simulations. The polymer-nanoparticle attraction leads to good dispersion of nanoparticles. We observe an increase in the number of topological constraints (...

Individual entanglements in a simulated polymer melt.

Since the first theories of rubber elasticity, the notion of entanglement between polymer chains has been a central component [1]. Conceptually these entanglements are viewed as discrete constraints that limit the configurations of the chains, reduce their randomness, and thus contribute to the entropic stress in the rubber. These same entanglements are thought to be present in polymer melts. H...

The tube axis and entanglements in polymer melts.

Although the tube theory is very popular and successful, the tube concept remains evasive and ill defined. This paper proposes a simple computer algorithm to construct the tube axis as a center line of the cloud of chain configurations at different moments of time. We test this algorithm on trajectories generated from simulations of concatenated well entangled ring polymers, thus avoiding all d...

Structure, entanglements and dynamics of polymer nanocomposites containing spherical nanoparticles

Strain hardening of polymer glasses: entanglements, energetics, and plasticity.

Simulations are used to examine the microscopic origins of strain hardening in polymer glasses. While stress-strain curves for a wide range of temperature can be fit to the functional form predicted by entropic network models, many other results are fundamentally inconsistent with the physical picture underlying these models. Stresses are too large to be entropic and have the wrong trend with t...