Advances in rheological characterisation

Several different characterisation methods are used routinely. These will now be considered in the context of how they apply to polymer variables and end-use requirements. 

As discussed in Section 3.3, synthetic acrylic polymers can be classified into three groups described here as types according to the following definitions  

Each of these product types has characteristic behaviours which can be recognised in one or more of the rheological profiles obtained from advanced characterisation methods. These are usually the characteristics which make a polymer well (or badly) suited to the end-use requirements. 

Recalling the range of shear rate values (see Table 3.2) that a paint or cosmetic formulation may be exposed to during manufacture, storage and use, it is apparent that this sort of measurement should cover values ranging over several orders of magnitude or more for both viscosity and shear rate. It is common to see this information presented graphically as log viscosity versus log shear rate. 

A recent exercise [30] examined polymers selected to be representative of each of the three product types referred to above and the information presented in the graphs which follow is taken from this study. Details of the polymers used are given below  

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