The document contains 3 questions regarding polymer rheology from a textbook on polymer systems: 1. A polymer sample in a viscometer will move a distance in 10 seconds given its shear stress-shear rate relationship and the viscometer parameters. 2. A polyacrylamide solution's Huggins plot data can be used to predict its specific viscosity at a given concentration using the Martin equation. 3. An empirical shear stress-shear rate model for a polymer sample is given. Using the zero-shear viscosity and a viscosity-stress point, the viscosity at a given shear rate can be calculated.

1. HE – Unit 5
Q.5.1 (Prb. 7.32 in Principles of Polymer Systems, F. Rodriguez, Taylor and Francis)
If 0.500 cm3 of polymer described by the following model is placed in a parallel-plate
viscometer with a plate separation of 0.0100 cm and if a weight of 0.500 g is applied
to the movable plate by appropriate pulleys, how far will the plate move in 10 s? τ is
in Pa.
Model: γ = 2.00 × 10 − 2 τ2
&

2. Q.5.2. (Prb.7.10. Principles of Polymer Systems, F. Rodriguez, Taylor and Francis) A sample of
polyacrylamide forms solutions in water that can be fitted by a Huggins equation plot
over the range of 1.0<ηr<1.5 with a slope of 0.700 (g/dl)2 and an intercept of
1.35 dl/g. If the data from the Huggins equation at relative viscosities of 1.0 and 1.5
are used to fit the Martin equation, what specific viscosity can be predicted at a
concentration of 5.0 g/dl?

3. Q.5.3. (Prb.7.20 in Principles of Polymer Systems, F. Rodriguez, Taylor and Francis) An
empirical equation relating stress τ to rate of shear γ contains two constants, A and B.
&
Aγ
&
τ=
1+ B γ
&
Given that the zero-shear viscosity is 10 Pa⋅s for a certain sample and that the
viscosity is 1.0 Pa⋅s at a stress of 103 Pa, calculate the viscosity at a rate of shear of
4×103 s-1.