Polymer Processing I

Polymer processing method can be used to change the microstructure of polymer chains.

• True

• False

Which of the followings are the criteria for Newtonian Fluid?

• Viscosity is constant at all shear rate

• Macromolecules

• Does not have any interaction between between the molecules

• Does not have entanglement

Which of the followings are TRUE statement about entanglement?

• Entanglement is cause by cross linking

• Entanglement is cause by physical hook

• Net changes in entanglement upon application of shear will result in changes in viscosity

• Entanglement is caused by Van der Waal forces

In shear thickening solutions, the shear thickening behavior is influenced by the followings EXCEPT

• Interparticle forces stability

• Shear value

• Entanglement

• Concentration of suspended particles

In Bingham plastic the flow could only observed when the shear stress applied exceed ----------------------

The following regions could be observed for polymer melts subjected to a range of shear.

• Low shear regions

• Constant shear region

• High shear region

• Shear thinning regions

Select the correct answers.

The viscosity vs shear rate graph was plotted for LDPE and HDPE. Which of the followings are true.

• At low shear region, LDPE shows higher viscosity compared to HDPE

• At shear thinning region, drop of viscosity is more for HDPE

• At high shear region both HDPE and LDPE behaves as Newtonian fluid.

List two processing parameters that could effect the shear thinning properties of polymers in extruder?

Tick all the correct statements.

• Increase in pressure reduces shear thinning effect.

• Increase in branching of polymer reduces shear thinning effect.

• Increase in temperature increase shear thinning effect.

• Plasticizer reduces shear thinning effect.

Fillers effect on viscosity of polymer melt in influenced by the followings EXCEPT

• Loading of fillers

• Shape of filler

• Surface area of filler

• Crystallinity of filler