Fall_2005_Exam_2 - POLYMER PROCESSING - FALL 2005 EMA 4666C...

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POLYMER PROCESSING - FALL 2005 NAME: PUT ON LAST PAGE and SIGN HONOR CODE EMA 4666C – EXAM 2 STUDENT #:______________________ INSTRUCTIONS: Read the entire exam carefully . Answer every question to the best of your ability, based upon the available information. State all assumptions in answers. SECTION I: Polymer Structures/Properties. (2 pts each/12 pts total) 1. Draw the structural repeat units for the following polymers. 2. Indicate the type of polymerization process used to synthesize each of the structures, i.e. condensation, addition, ring opening. 3. State the relative Tg and/or Tm for each polymer. If a Tm is not expected indicate by NA. Polymer Structural Repeat Unit Process Tg Tm 1. poly(ethylene) 2. poly(bis phenol A carbonate) 3. poly(caprolactam) (Nylon 6) 4. poly(propylene) 5. poly(butadiene) 6. poly(vinyl chloride)
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Student Number:___________________________ Concepts. (2pts ea/12pts total) Answer the following statements with TRUE or FALSE . If the statement is false, state the reason(s). If you believe a statement can be made TRUE by a simple qualifier, then state it clearly. 7. The Pressure Output of an extruder is proportional to the diameter raised to the second power. 8. The melt pool on the extruder screw accumulates ahead of the pellets relative to the direction of transport along the barrel. 9. The frostline distance from the die on a film tower decreases as the blow pressure is increased. 10. The parison wall thickness at the die, i.e., die swell, increases as shear rate is decreased. 11. Laminar flow has a dimensionless Reynolds number of greater than 2100. 12. Lamellae thickness increases in a HDPE extruded film for a given die temperature and ambient temperature as the melt temperature is reduced. EMA 4666C Fall 2005 Exam 2 2
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Student Number:___________________________ Graphical Relationships: A. SHOW ALL EQUATIONS. B. EACH GRAPH SHOULD BE A LINEAR RELATIONSHIP. C. LABEL ALL AXES WITH THE APPROPRIATE UNITS. D. CLEARLY STATE ALL ASSUMPTIONS . 13. Sketch the relationship (linear graph) of the Pressure Output versus Temperature for a simple film die. 3 pts 14. Sketch the relationship between melt viscosity for an extruder screw with a constant channel height and the pressure gradient, i.e. metering zone.
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Fall_2005_Exam_2 - POLYMER PROCESSING - FALL 2005 EMA 4666C...

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