# data[].attributes.body
This tells us that most object are viscous and elastic at the same time. (G''=G', around 45 degrees)

# data[].attributes.body
G': storage module (solid-like: spring). The capacity of the object able to store energy
G'': Loss modulus (viscous-like). The part that energy are being lost to heat due to friction

If the angle of g prime is more than 45 degree(closer to G''): then the material will behave more like liquid. Higher loss modulus than storage modulus

If the angle of g prime is less than 45 degree (closer to G'): the material will behave more like solid. Higher storage modules than loss modulus

If the g complex lies at 45 degree, then it behaves half like solid and half liquid at the same time (posses both properties)

# data[].attributes.body
G=Shear stress/ shear strain.

Shear stress can be found using: shear force(F)/surface area(A)

Shear strain can be found: deflection path(s)/shear gap(h)

The higher the G value, the stiffer the material. This means that a larger force is required to produce deformation.

# data[].attributes.body
Measure store and energy loss without destroying the object itself. (viscoelastic properties)

# data[].attributes.body
Long term storage behaviour of dispersion in lower frequency range
If G'>G", solid structure is caused by stable network of forces
If G">G', material is liquid and susceptible to segregation

# data[].attributes.body
Uncrossedlinked polymer
Low frequency, G">G'
Crossover point G' = G" = the value of angular frequency
If crossover occurs at lower frequency, material has higher molar mass
Crosslinked polymer
G' > G"
G' value at lower frequency can be used to compare the crosslinking density of different samples
Higher G' value, stiffer the material, higher degree of crosslinking

# data[].attributes.body
Frequency sweep...
- constant amplitude
- constant temperature
- varying frequency

Test determines...
- molecular weight
- molecular weight distribution
- degree of crosslinking
- stability
- impact resistance

# data[].attributes.body
Ty (yield point/ stress yield):
- Shear stress limit of the LVE region.
- “to yield” means to give way or to soften
- This point is also called the linearity limit.

Tf (flow point/flow stress):
- The shear stress value at the crossover point G' = G''.

- At higher shear, the viscous portion will dominate à the sample flows

# data[].attributes.body
•G' > G'‘ - a gel-like / solid structure -  viscoelastic solid material.

•G'' > G' - a fluid structure - viscoelastic liquid.

# data[].attributes.body
Indicates range in which test can be carried out without destroying the structure of the sample

Shows plateau (constant) value

# data[].attributes.body
deflection of the measuring system is increased step-wise from one measuring point to the next while keeping frequency at a constant value.

Test determines:
Linear viscoelastic region
Structural strength
Rigidity (stiffness)
Structural stability
Dynamic yield point and flow point (for viscoelastic solids)

# data[].attributes.headline
non newtonian fluid: thixotropic and rheopectic

# data[].attributes.subject
non newtonian fluid: thixotropic and rheopectic

# data[].attributes.body
these are fluids that have flow behaviour based on time(time dependant)

thixotropic fluid: Viscosity decreases with time at constant shear rate
rheopectic fluid: Viscosity increases with time at constant shear rate

# data[].attributes.body
viscosity increases as shear rate increases.
for example, more strength used to stir corn starch results in corn starch being more viscous

# data[].attributes.body
shear stress to shear rate graph is increasing non linearly

# data[].attributes.body
viscocity decreases as shear rate increases.
for example, more strength used to mix yoghurt, the less viscous the yoghurt becomes

# data[].attributes.body
shear stress to shear rate graph: increases non linearly.

# data[].attributes.body
viscocity vs shear rate graph: constant viscocity as shear rate increases, constant viscocity with time

# data[].attributes.body
-ideally viscous flow behaviour
-viscocity is not dependant on shear/applied rate

relationship between shear stress and shear rate: straight line

# data[].attributes.body
rotational viscometer
- measures fluid viscosity at fixed rotation speed
- uses a spindle in test fluid
- usually gives viscosity at a single shear rate
- measures dynamic viscosity

rheometers
- automatically measure viscosity over specified shear rate or time range
- measures viscosity values in continuous run
- provides a rheology profile in an experiment