Fall_2009_Exam3_ver_a - POLYMER PROCESSING FALL 2009 EMA...

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POLYMER PROCESSING - FALL 2009 NAME: PUT ON LAST PAGE and SIGN HONOR CODE EMA 4161C Exam 3 STUDENT #:______________________ EMA 4161C Fall 2009 Exam 3 ver a 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. (3 pts each/24 pts total) 1. Indicate the type of polymerization process used to synthesize each of the structures, i.e. condensation, addition, ring opening. 2. State the relative Tg and/or Tm for each polymer. If neither are measurable indicate by NA. 3. Specify stereoregularity as required by structure. Polymer Process Tg Tm 1. Poly(hexamethylene adipamide) 2. Poly(bisphenol A carbonate) 3. poly(caprolactone) (Nylon 6) 4. Poly(propylene) 5. Poly(butadiene) 6. Poly(styrene) 7. Poly(dimethylsiloxane) 8. Poly(ethylene oxide) SECTION II: 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. HINT: Normally one word can be modified to correct false statements. 9. The thickness of the transcrystalline zone of an injection-molded part is dependent on mold temperature. 10. The Reynolds number is inversely proportional the melt velocity raised to the second power.
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Student Number:___________________________ EMA 4161C Fall 2009 Exam 3 ver b 2 11. Die output scales directly with the flight angle of the extruder screw. 12. Die output for a tube on an extruder is directly proportional to the diameter raised to the first power. 13. The breaker plate induces memory into the polymer extrudate. 14. Pressure flow through a channel of fixed dimensions scales inversely with the strain rate of a newtonian fluid. SECTION III: Graphical Relationships (NEXT PAGE): A. SHOW ALL EQUATIONS. B. IF POSSIBLE, REPRESENT EACH GRAPH AS A LINEAR RELATIONSHIP. C. LABEL ALL AXES WITH THE APPROPRIATE UNITS AND CRITICAL TRANSITIONS. D. CLEARLY STATE ANY/ALL ASSUMPTIONS.
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Student Number:___________________________ EMA 4161C Fall 2009 Exam 3 ver b 3 15. Sketch the behavior of the mold fill time t e P f o k T T B  ( ) * ( ) with respect to the die output, i.e., simple Poisuelle Flow (assume newtonian behavior, i.e.). Variables: t: time (sec); alpha and beta: machine constants; k: constant for temperature effect on viscosity; P B is the nozzle pressure; T: stock temperature; T*: reference temperature 4 pts 16. Sketch the Tm as a function of stem length using Hoffman crystallization model. 4 pts
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Student Number:___________________________ EMA 4161C Fall 2009 Exam 3 ver b 4 SECTION IV: Definitions/Concepts. (2 ea/24 pts Total) Give a BRIEF description for each of the following terms in the SPACE provided.
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