The rheology toolkit is a series of short articles exploring some fundamental rheological tests that can be used to generate information for formulation, product development, QC and process troubleshooting.
Some people would argue that rheology is an underused characterisation technique.
However, it can be difficult for non-experts to decide what to measure and what the measurements mean in practice.
The rheological properties of all kinds of products are routinely manipulated to achieve desired performance characteristics, whether by trial and error or using the information provided by measuring specific parameters.
This applies whether you are suspending abrasive beads in personal care products, making a diet food creamy and appetising, or ensuring that paint spreads easily across a surface, but does not drip.
While in many cases it may be possible to reach performance goals through trial and error, formulators who can successfully measure and adjust rheological properties have the advantage of being able to take a more efficient, knowledge-led approach.
Systematically working towards a well-defined target is quicker and easier than incremental, empirical evolution.
This article marks the start of a new series in which Steve Carrington, product marketing manager for rheology at Malvern Instruments, introduces some of the most useful rheological test methods.
Each addition to the series will focus on a single test, explaining how it works, the information it generates and why it might be useful. The aim is to showcase the rheology toolkit, a collection of techniques that can be used on a routine basis to help develop products that deliver to the required specifications and attributes.
The use of ’toolkit’ tests enables a ’picture’ of the overall rheology of a material to be built up - analogous to putting together the pieces of a puzzle to find a solution to material formulation, application or process problems.
By comparing and contrasting the results of these tests for different formulations, or for ’good and bad’ samples, time can be more effectively spent in targeted optimization of a key material characteristic, or implementation of a critical diagnostic test.
The series is intended to be of interest to any scientist or engineer wanting to find out more about how rheology might work for them.
