Publication

Rheological behavior of hyperbranched polymer/montmorillonite clay nanocomposites

Jan-Anders Edvin Maansson, Yves Leterrier, John Christopher Plummer
2004
Journal Articles

Abstract

The equilibrium rheological properties of a range of isotropic exfoliated and intercalated hyperbranched polymer (HBP)/montmorillonite (MMT) clay nanocomposites have been investigated using low strain oscillating shear measurements at temperatures above the glass transition temperature of the HBP. Predominantly exfoliated nanocomposites showed a sharp increase in shear viscosity at about 0.8 wt % MMT, associated with a transition from Newtonian to solid-like behavior, which was characterized in terms of a limiting shear modulus at low frequencies and a limiting viscosity at high frequencies, both of which were strongly dependent on the MMT content. Intercalated HBP/organically modified MMT nanocomposites showed qualitatively similar behavior, but the increase in viscosity with MMT content was far weaker. This was argued to reflect a significantly lower effective particle aspect ratio than in the exfoliated nanocomposites.

Official source

https://infoscience.epfl.ch/entities/publication/1c53df0c-bf0e-43b3-8d89-da23114f6553

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Jan-Anders Edvin Maansson, Yves Leterrier, John Christopher Plummer
2004
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/1c53df0c-bf0e-43b3-8d89-da23114f6553

About this result

Related concepts (31)

Viscosity

The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity is defined scientifically as a force multiplied by a time divided by an area. Thus its SI units are newton-seconds per square metre, or pascal-seconds. Viscosity quantifies the internal frictional force between adjacent layers of fluid that are in relative motion.

Shear stress

Shear stress (often denoted by τ (Greek: tau)) is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. Normal stress, on the other hand, arises from the force vector component perpendicular to the material cross section on which it acts. The formula to calculate average shear stress is force per unit area.: where: τ = the shear stress; F = the force applied; A = the cross-sectional area of material with area parallel to the applied force vector.

Rheology

Rheology (riːˈɒlədʒi; ) is the study of the flow of matter, primarily in a fluid (liquid or gas) state, but also as "soft solids" or solids under conditions in which they respond with plastic flow rather than deforming elastically in response to an applied force. Rheology is a branch of physics, and it is the science that deals with the deformation and flow of materials, both solids and liquids. The term rheology was coined by Eugene C. Bingham, a professor at Lafayette College, in 1920, from a suggestion by a colleague, Markus Reiner.