Conexiant
Login
  • The Analytical Scientist
  • The Cannabis Scientist
  • The Medicine Maker
  • The Ophthalmologist
  • The Pathologist
  • The Traditional Scientist
The Analytical Scientist
  • Explore

    Explore

    • Latest
    • News & Research
    • Trends & Challenges
    • Keynote Interviews
    • Opinion & Personal Narratives
    • Product Profiles
    • App Notes

    Featured Topics

    • Mass Spectrometry
    • Chromatography
    • Spectroscopy

    Issues

    • Latest Issue
    • Archive
  • Topics

    Techniques & Tools

    • Mass Spectrometry
    • Chromatography
    • Spectroscopy
    • Microscopy
    • Sensors
    • Data and AI

    • View All Topics

    Applications & Fields

    • Clinical
    • Environmental
    • Food, Beverage & Agriculture
    • Pharma and Biopharma
    • Omics
    • Forensics
  • People & Profiles

    People & Profiles

    • Power List
    • Voices in the Community
    • Sitting Down With
    • Authors & Contributors
  • Business & Education

    Business & Education

    • Innovation
    • Business & Entrepreneurship
    • Career Pathways
  • Events
    • Live Events
    • Webinars
  • Multimedia
    • Video
Subscribe
Subscribe

False

The Analytical Scientist / App Notes / 2018 / Using the Power Law Model to Quantify Shear Thinning Behavior on a Rotational Rheometer

Using the Power Law Model to Quantify Shear Thinning Behavior on a Rotational Rheometer

05/23/2018

Share

Featured Image

Abstract

A material’s rheological properties not only influences its visual and textural perception, but also affects its processing capabilities. For instance, compared to Newtonian materials, shear-thinning materials are more susceptible to applied stress.

Introduction

While most suspensions and polymer structured materials are shear thinning, some materials can also show shear thickening behavior where viscosity increases with increasing shear rate or shear stress. This phenomenon is also often referred to as dilatancy, and although this refers to a specific mechanism for shear thickening the terms are often used interchangeably. In most cases, shear thickening occurs over a decade of shear rates and there can be a region of shear thinning at lower and higher shear rates.

Usually dispersions or particulate suspensions with high concentration of solid particles, pastes, associative polymers such as HASE, HEUR polymers etc. exhibit shear thickening. Materials exhibiting shear thickening are much less common in industrial applications than materials exhibiting shear thinning, however, where encountered shear thickening materials can lead to severe processing problems. Materials which undergo micro-structural or orientation changes on application of shear, that lead to increased resistance to flow, will tend to show shear thickening.

For suspensions this generally occurs in materials that show shear thinning at lower shear rates and shear stresses. At a critical shear stress or shear rate the organized flow regime responsible for shear thinning, is disrupted and so called ‘hydro-cluster’ formation or ‘jamming’ can occur. This gives a transient solidlike response and an increase in the observed viscosity. Shear thickening can also occur in polymers, in particular amphiphilic polymers, which at high shear rates may open-up and stretch, exposing parts of the chain capable of forming transient intermolecular associations.

Mathematically the shear thickening behavior can be modeled using the powerlaw model; Where: k is the consistency
η is the power law index
σ is the shear stress
ý is the shear rate With n greater than 1 for shear thickening fluids. It should be noted that an upturn in viscosity at high shear rates can occur through other phenomenon such as fluid turbulence. This effect, however, tends to occur with lower viscosity fluids and can be predicted from Reynolds number calculations.
>> Download the full Application Note as PDF

Newsletters

Receive the latest analytical scientist news, personalities, education, and career development – weekly to your inbox.

Newsletter Signup Image

Explore More in Analytical Science

Dive deeper into the analytical science. Explore the latest articles, case studies, expert insights, and groundbreaking research.

False

Advertisement

Recommended

False

Related Content

Download the latest Lab Trends Report
Download the latest Lab Trends Report

January 8, 2018

To better understand the view from the lab, we asked nearly 500 scientists some searching questions...

Confocal Raman Imaging – Depth profiling of polymer films and coatings
Confocal Raman Imaging – Depth profiling of polymer films and coatings

January 16, 2018

This application note demonstrates how confocal Raman imaging is capable of acquiring depth profiles of polymers coatings that allow individual layers to be distinguished and measured...

Real-Time Speciation of Ethylbenzene from the Xylenes Using Direct MS
Real-Time Speciation of Ethylbenzene from the Xylenes Using Direct MS

January 18, 2018

This application note describes how selected ion flow tube mass spectrometry (SIFT-MS) readily achieves real-time speciation of the xylenes from ethylbenzene...

Monitoring and Controlling the Electrode Particle Characteristics and Viscosity of Battery Slurries
Monitoring and Controlling the Electrode Particle Characteristics and Viscosity of Battery Slurries

January 26, 2018

Using Morphologi G3 to monitor and control the electrode particle characteristics and viscosity of battery slurries...

False

The Analytical Scientist
Subscribe

About

  • About Us
  • Work at Conexiant Europe
  • Terms and Conditions
  • Privacy Policy
  • Advertise With Us
  • Contact Us

Copyright © 2025 Texere Publishing Limited (trading as Conexiant), with registered number 08113419 whose registered office is at Booths No. 1, Booths Park, Chelford Road, Knutsford, England, WA16 8GS.