Table 4.
Rheology – methods, parameters and descriptions
| Method | Parameter | Description |
|---|---|---|
| Solid products | ||
| Penetration test | Maximum load | The maximum force reached when pushing a probe through the sample |
| Penetration test | Strain at maximum load | Percentage of the sample penetrated when the maximum force is reached |
| Penetration test | Young's modulus | A measure of the stiffness of the sample derived from the penetration test |
| Oscillatory test | G′ (storage modulus)/G″ (loss modulus) | G′ represents the elastic behavior of the sample. G″ represents the viscous behavior of the sample. A higher value means more resistance to deformation |
| Oscillatory test | ||
| Oscillatory test | Δ (phase angel) | Relation between G′ and G″. 0° is a completely elastic material and 90° a completely viscous material |
| Liquid products | ||
| Shear viscosity | K and n are derived from model adaptation to viscosity measurements at several different shear rates. This allows the behavior of a fluid over a range of shear rates to be described with two parameters | |
| Shear viscosity | K (Consistence index) | K is a measure of the fluid thickness. K is equal to the viscosity at the shear rate 1s–1 |
| Shear viscosity | n (Shear thinning exponent) | Describes a fluid's behavior depending on shear rates. 1, Newtonian; <1, shear thinning (i.e. the samples had a lower viscosity at higher rate); >1, shear thickening (i.e. samples have a higher viscosity at higher rate) |
| Extensional viscosity | Kext and next are derived from model adaptation to extensional viscosity measurements at several different extension rates. This allows the behavior of a fluid over a range of extension rates to be described with two parameters | |
| Extensional viscosity | Kext | Kext is a measure of the fluid thickness. Kext is equal to the extensional viscosity at the extension rate 1s–1 |
| Extensional viscosity | next (Tension thinning exponent) | Describes a fluid's behavior depending on extension rates. |
| 1, Newtonian; <1, tension thinning (i.e. the samples had a lower viscosity at higher rate); >1, tension thickening (i.e. samples have a higher viscosity at higher rate) | ||