The viscosity-radius relationship for concentrated polymer solutions

Relationship Dynamic Viscosity and Inverse Absolute Temperature to the Concentrated Solutions

This paper presets the study of the rheological characteristics of the concentrated polyethylene-polypropylene copolymer solutions over the temperature range of 313-363 K and for shear rates between 3 and 1312 s-1. The measurements were performed on a Haake VT 550 rotational rheometer with a HV1 sensor. The rheology of the concentrated solutions is influenced by the shear rate, temperature and ...

Concentrated polymer solutions in the presence of fixed obstacles

Viscosity Solutions for a Polymer Crystal Growth Model

We prove existence of a solution for a polymer crystal growth model describing the movement of a front (Γ(t)) evolving with a nonlocal velocity. In this model the nonlocal velocity is linked to the solution of a heat equation with source δΓ. The proof relies on new regularity results for the eikonal equation, in which the velocity is positive but merely measurable in time and with Hölder bounds...

Diffusion Coefficients in Polymer- Solvent Systems for Highly Concentrated Polymer Solutions

The Vrentas/Duda proposal for the diffusion of polymer-solvent systems, which is based on the free-volume theory, was employed in correlating and predicting mutual diffusion coefficients in highly concentrated polymer solutions. It has been observed that the predictive version of the model is capable of qualitatively representing the experimental data, while the use of an adjustable parameter g...

Entanglement-controlled subdiffusion of nanoparticles within concentrated polymer solutions.

We describe x-ray photon correlation spectroscopy (XPCS) experiments tracking the motion of gold nanoparticles within solutions of high-molecular-weight polystyrene. Over displacements from nanometers to tens of nanometers, the particles undergo subdiffusive motion that is dictated by the temporal evolution of the entangled polymer mesh in the immediate vicinity of the particles. The results th...