exam

1. ‫بسم‬‫ال‬‫الرحمن‬‫الر‬‫حيم‬
KING SAUD UNIVERSITY
College of Engineering
Chemical Engineering Department
CHE 422 Selected Topics in chemical Engineering
"Polymer Science and Engineering"
Instructor: Dr.Fahad S Al-Mubaddel
Final exam spring 1427 H , SUNDAY 1/5/1427 H
_____________________________________________________________________
Student Name:-…………………………….………………..Student No……………-:.
_____________________________________________________________________
Q1: a) Shown below is the shear-rate dependent viscosity of a polymeric fluid.
Identify the "power-law" region of this data, and estimate the power-law exponent, n
b) Derive the Equation of State of an Ideal rubber!
Q2: For a series of Polystyrene samples, in a mixed solution at 298 K, the intrinsic
viscosity[η] vs. M.Wt. data are as follows:
[η] (cm3
/g) 38.2 59.2 69.6 105.4 129.3 165 221
M(1000 Daltons) 76 135 163 336 440 556 850
Find the corresponding Mark-Houwink-Sakurada Equation parameters!.
1

2. KING SAUD UNIVERSITY
College of Engineering
Chemical Engineering Department
CHE 422 Selected Topics in chemical Engineering
"Polymer Science and Engineering"
Instructor: Dr.Fahad S Al-Mubaddel
Final exam spring 1427 H , SUNDAY 1/5/1427 H
_____________________________________________________________________
Student Name:-…………………………….………………..Student No……………-:.
_____________________________________________________________________
Q3: Draw The Characteristic Curve for a 45 mm Melt Extruder for a rotational
speed of N=60 rpm. The extruder has a square pitch, an L/D ratio of 20, An angle of
17.65, a constant channel depth of 2.5 mm, a channel width of 37.88, and a clearance
of 0.15
Assume a Newton’s law viscosity of 100 Pa-s
Steps:
Compute velocity:,
Compute channel Length:Lc=((L/D)D/Sin theta))
Compute Drag shape Factor Fd:
And Pressure Fp Shape Factors
Compute leakage flow factor:
Compute Flow rate:
Plot flow rate vs ΔP!
2

3. KING SAUD UNIVERSITY
College of Engineering
Chemical Engineering Department
CHE 422 Selected Topics in chemical Engineering
"Polymer Science and Engineering"
Instructor: Dr.Fahad S Al-Mubaddel
Final exam spring 1427 H , SUNDAY 1/5/1427 H
_____________________________________________________________________
Student Name:-…………………………….………………..Student No……………-:.
_____________________________________________________________________
Q4:A power law polymeric solution is characterized using a cone-and-plate
viscometer(cone angle =0.50 degrees) Measured viscosity is 0.200 Pa.s at 6 rpm and
0.08 Pa.s at 60 rpm. What value of Dp/L is required to produce a volumetric flow rate
of 1 liter/s of this solution in a horizontal pipelind inner diameter 2 cm ? ( hint: you
are required to find power law model parameters n & K first to solve the problem!)
Q5
a) For a freezing point depression of 0.5 o
C of a solution of 1 gm of
Polyethylene ( M2=500) in 100 gm of camphor (Tf=178.4 o
C, M1=152), find the latent
heat of fusion for camphor ΔHf!
b) The Voigt ( or Kelvin) element of representing viscoelastic behavior of polymers
resembles the Maxwell elements except that the spring and dashpot are in
parallel rather than in series. Show that the creep compliance of such an
element is given by
Where E is the Modulus and η is the viscosity!
3