GATE XE Polymer rheology PYQs & Answers

Questions 1–10 of 27. Imported answers require independent review unless marked reviewed.

Which one of the following is NOT a rotational rheometer?

Your answerChoose one option.

Cone and plate rheometer

Parallel plate rheometer

Capillary rheometer

Cylindrical Couette rheometer

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The variation of steady shear viscosity (

) of a polymer melt with shear rate (

) is shown in the figure, where

is the upper limit of the applied shear rate. Which one of the following figures, labeled P, Q, R and S, shows the most appropriate variation of shear stress (

) with shear rate for the same polymer melt?

Diagram for Engineering Sciences question 123

Diagram for Engineering Sciences question 123 (figure 2)

Your answerChoose one option.

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A viscoelastic polymer is subjected to a constant strain of 0.3. The behavior of the polymer follows Maxwell model of linear viscoelasticity. Elastic modulus of the polymer is 5 MPa and the relaxation time is 200 days. The stress in the polymer after 100 days from the initial application of the strain is ______________ MPa (rounded off to two decimal places).

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The ‘die swell’ phenomenon exhibited by a polymer melt is due to

Your answerChoose one option.

viscos deformation

plastic deformation

viscous and elastic deformation

elastic recovery

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For a polymer solution, the dependence of viscosity (

) on shear rate (

) is described by the three-parameter Carreau model given by

where,

, and

are the three parameters of the model. Here, all three parameters are positive quantities. As the shear rate increases from 1 s

to 100 s

, the viscosity of the polymer solution decreases by a factor of 10. For a polymer solution with

and

Pa s, the value of the parameter

is ______ s (rounded off to two decimal places).

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The linear viscoelastic behavior of a polymer is described by the Kelvin-Voigt model consisting of a spring element of elastic modulus 10 MPa in parallel with a dashpot of viscosity 3.6 × 10

Pa s. A fixed stress of 40 MPa is suddenly applied to the polymer and maintained thereafter. The value of the strain after one hour from the sudden application of the stress is ______ (rounded off to two decimal places).

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A copper wire upon loading instantaneously increases in length to l, and then continues to elongate gradually. Upon unloading, the wire retracts to length l. According to the Maxwell model, which one of the options given correctly relates the total strain E, the applied stress S, the modulus G, the material’s resistance to flow η, and the elapsed time t between loading and unloading?

Your answerChoose one option.

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Which of the following statements is NOT correct?

Your answerChoose one option.

As the shear rate increases, the apparent viscosity decreases for a pseudoplastic fluid.

As the shear rate increases, the apparent viscosity increases for a dilatant fluid.

A Bingham fluid requires application of yield stress prior to any response.

Rheopectic and thixotropic are two time independent fluids.

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From the dynamic mechanical analysis of a polymer sample with a phase angle of 30°, the relationship between storage modulus (E') and loss modulus (E'') can be expressed as

Your answerChoose one option.

E' = √3 E''

2E' = √3 E''

E'' = √3 E'

2E'' = √3 E'

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For a polymer sample with a viscosity of

poise, if the apparent plateau modulus of

dyne cm

drops to zero above a certain temperature, the relaxation time of the polymer is ________ days (rounded off to one decimal place).

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GATE XE Polymer rheology PYQs

How to practice Polymer rheology

Question 114

Question 123

Question 130

Question 115

Question 129

Question 131

Question 111

Question 137

Question 119

Question 127