AI L6 Mindmap by LEE BING XUN https://padlet.com/21014674_2/jyajjbv9albqw5rl en-us 2022-11-25 04:27:53 UTC 2025-11-08 20:12:29 UTC hello@padlet.com Lesson 6 (Physical Tests: Rheology) 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397535437 2022-11-25 04:51:04 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397535437 Shear Rate 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397542419 Shear Rate  = (Difference in "velocity" )/(S hear gap (h))
Unit= (m/s) /m  = 1 /s 
]]> 2022-11-25 04:59:22 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397542419 Shear Stress 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397543997 Shear Stress =  Shear Force (F)/Surface Area (A)
Unit = N /m^2 = Pa
]]> 2022-11-25 05:01:26 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397543997 Viscosity 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397549313 Viscosity = Shear stress (τ)/( Shear Rate (g))
Unit = Pa /(1/s) = Pa.s (Pascal second)
Viscosity of everyday material at 25 degrees Celsius  ]]> 2022-11-25 05:08:17 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397549313 Flow behavior types 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397550876 2022-11-25 05:10:17 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397550876 Newtonian fluid 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397555134 Ideally viscous flow behaviour.
Viscosity is not dependant on shear applied/ shear rate. 
Shear stress and shear rate are directly proportional 
Viscosity is unimpacted by the shear rate
]]> 2022-11-25 05:15:58 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397555134 Non-Newtonian Fluid Shear Thinning=(Pseudoplastic) Flow 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397564132 shear stress increases at a decreasing rate until it plateau against shear rate.
viscosity decreases when shear rate increases ]]> 2022-11-25 05:27:55 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397564132 Non-Newtonian Fluid Shear Thickening (Dilatant) Flow 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397569525 Shear stress increases at an increasing rate of shear rate.
Viscosity increases at an increasing rate of shear rate. 


]]> 2022-11-25 05:36:58 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397569525 Shear dependant 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397570571 2022-11-25 05:38:47 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397570571 Time dependant 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397571291 2022-11-25 05:39:57 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397571291 Thixotropic 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397574221 viscosity decreases as time progresses]]> 2022-11-25 05:44:42 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397574221 Rheopectic 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397574305 viscosity increases as time progresses]]> 2022-11-25 05:44:50 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397574305 Yield point evaluation 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397576371 2022-11-25 05:48:10 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397576371 Non-Newtonian Fluid (Bingham plastic) 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397577999 Bingham plastic fluid will behave as a solid under static conditions. 
Yield stress is the force required to make the status change.
A substance without yield point will flow directly. A Substance with yield point don’t flow immediately when sheared but only after certain amount of force applied.  
Once the yield value is exceeded, Bingham Plastic fluids may display Newtonian, pseudoplastic or dilatant flow characteristics.]]> 2022-11-25 05:50:49 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397577999 Instrument to measure flow behavior 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397580293 2022-11-25 05:54:19 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397580293 Rotational Viscometer 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397584245 measures fluid viscosity at fixed rotation speeds by immersing a spindle in the test fluid
gives a viscosity at a single shear rate. 
Dynamic viscosity is measured]]> 2022-11-25 06:00:01 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397584245 rotational tests 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397586000 2022-11-25 06:02:29 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397586000 Rheometers 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397587743 an instrument that can automatically adjust itself to measure viscosity over a specified shear rate or time range.
It measures many viscosity values in a continuous run under changing conditions (shear rate or time) to provide a rheology profile in one single experiment. ]]> 2022-11-25 06:05:08 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397587743 Oscillatory tests 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397588985 measure viscoelastic properties]]> 2022-11-25 06:07:07 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397588985 Elasticity 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397602168 is the ability of a material to return to its original form  after a load has been applied and removed. 
Shear modulus, G describes the deformation behavior of a material the stiffness of material.]]> 2022-11-25 06:27:16 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397602168 Shear Stress 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397609097 Shear Stress= Shear Force (F) /Surface Area (A)
Unit = N /(m^2) = Pa
]]> 2022-11-25 06:37:30 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397609097 Shear strain or shear deformation 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397613476 Shear strain or shear deformation (g) =deflection path (s) /Shear gap (h)
Unit= m /m = 1 (dimensionless)
]]> 2022-11-25 06:43:07 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397613476 Shear Modulus 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397631148 Shear modulus (G) = Shear stress (t) /shear strain(g)  
Unit = Pa /dimensionless  = Pa (Pascal)
For solids and viscoelastic solids.
The higher the G value, the stiffer the material.
]]> 2022-11-25 07:07:34 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397631148 Measurement of viscoelasticity (flow behavior) 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397640061 2022-11-25 07:17:38 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397640061 Energy storage 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397640778 2022-11-25 07:18:34 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397640778 Energy Loss 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397641034 2022-11-25 07:18:51 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397641034 viscous behavior 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397647099 G''
energy loss
loss modulus]]> 2022-11-25 07:26:37 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397647099 Elastic behavior 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397648405 G'
Energy storage
Storage modulus ]]> 2022-11-25 07:28:15 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397648405 Loss modulus G” 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397664271 Characterizes the deformation energy lost (dissipated) through internal friction when flowing
Viscous portion of viscoelastic behavior-> liquid state behavior of the sample]]> 2022-11-25 07:45:09 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397664271 Storage Modulus, G’ 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397667402 Represents the stored deformation energy
Elastic portion of viscoelastic behaviour- solid state behaviour of the sample ]]> 2022-11-25 07:48:31 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397667402 G’ and G” relation 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397672990 0 degrees purely elastic (solid) behavior
90 degrees purely viscous (liquid) behavior
Viscoelastic liquids G'' > G' - higher loss modulus than storage modulus
Viscoelastic solids G' > G” - higher storage modulus than loss modulus
]]> 2022-11-25 07:54:27 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397672990 Amplitude sweep 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397686350 The deflection of the measuring system is increased step-wise from one measuring point to the next while keeping frequency at a constant value.
Tests for Linear viscoelastic region, Structural strength, Rigidity (stiffness), Structural stability, Dynamic yield point and flow point (for viscoelastic solids)]]> 2022-11-25 08:09:23 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397686350 LVE region and linearity limit 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397694988 The LVE region indicates the range in which the test can be carried out without destroying the structure of the sample. 
It shows a constant value->plateau value. 
Limiting value of the LVE region->Linearity limit (before the straight line becomes non linear.)]]> 2022-11-25 08:16:05 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397694988 Yield point/ yield stress 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397696616 Shear stress limit of the LVE region. 
This point is also called the linearity limit.
]]> 2022-11-25 08:17:40 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397696616 Flow point/ flow stress 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397704568 The shear stress value at the crossover point G' = G''. 
At higher shear, the viscous portion will dominate->the sample flows.]]> 2022-11-25 08:26:41 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397704568 Frequency sweep 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397707697 Uses Constant amplitude, Constant temperature, Varying frequency 
Test for Molecular Weight, Molecular Weight Distribution, Degree of crosslinking, Stability, Impact resistance]]> 2022-11-25 08:29:52 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397707697 crosslinked polymer 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397977728 2022-11-25 13:20:04 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397977728 crosslinked polymer 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397987122 G’ > G”. 
G’ value at a lower frequency can be used for comparison of the crosslinking density of different samples. 
The higher the G’ value, the stiffer the material, the higher the degree of crosslinking. 
]]> 2022-11-25 13:30:42 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397987122 uncrossedlinked polymer 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397991713 At low frequency, G”> G’.
Crossover point G’ = G”  = the value of the angular frequency.
If the crossover point occurs at lower frequency, the material has a higher molar mass.
]]> 2022-11-25 13:35:59 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2397991713 Frequency sweep of a dispersion 21014674_2 https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2398003418 Long-term storage behaviour of dispersions is evaluated in the lower frequency range.
If G’> G”, the solid structure is caused by a stable network of forces.
If G”>G’, this indicates that material is liquid, and susceptible to segregation. 
]]> 2022-11-25 13:49:18 UTC https://padlet.com/21014674_2/jyajjbv9albqw5rl/wish/2398003418