EMA6165-Fall-2009-EXAM1-Edge

# EMA6165-Fall-2009-EXAM1-Edge - POLYMER PHYSICS Fall 2008...

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POLYMER PHYSICS Fall 2008 STUDENT UFID#:______________________ EMA 6165 - EXAM I (use the NEW UF ID No.) INSTRUCTIONS: Read the entire exam carefully. Answer every question to the best of your ability, based upon the available information. State all assumptions you use in answers. SECTION I: Polymer Structures/Properties. State the polymerization mechanism, i.e., condensation, addition, ring opening. State the relative Tg and/or Tm for each polymer. (20pts) Polymer Polymerization Mechanism (2pt) T g (1pt) T m (1pt) 1. poly(ethylene) 2. poly(styrene) 3. poly(dimethyl siloxane) 4. poly(butadiene) 5. poly(hexamethylene adipamide)

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POLYMER PHYSICS - Fall 2009 (EDGE) EMA 6165 - EXAM I 2 Concepts. 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. (Normally only a single word change is required.) (12 pts) 6. Chain diffusion initiates with the yield stress. 7. The third moment of the molar mass is defined as the Number Average Molar Mass. 8. The root mean square end to end distance defines the average distance between chain ends for a Gaussian Chain. 9. Chain branches decreases the radius of gyration relative to linear chains of the same molar mass.
POLYMER PHYSICS - Fall 2009 (EDGE) EMA 6165 - EXAM I 3 II. Graphical Relationships: 1. Each plot should be represented as a linear function if possible through algebraic manipulation. 2. You must provide all equations used to create the plot 3. Label all axes appropriately, i.e., provide units and orders of magnitude. 4. STATE ALL ASSUMPTIONS required. 10. 5 The Characteristic Ratio versus the Intrinsic Viscosity for a linear polyethylene (6pts) 11. Given a perfectly elastic, ideal chain, plot the ultimate stress as a function of the mean square end to end distance. Show all equations! (6pts)

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POLYMER PHYSICS - Fall 2009 (EDGE) EMA 6165 - EXAM I 4 SECTION II: Definitions/Concepts: Give a BRIEF description for each of the following terms in the SPACE provided. Use equations or words or figures. 16 pts, 12. Tm: 13. <Mw>: 14. PDI: 15. Chain conformation: 16. Equation of state: 17. Phantom network: 18. Molecular weight between cross links: 19. Chain expansion factor :
POLYMER PHYSICS - Fall 2009 (EDGE) EMA 6165 - EXAM I 5 SECTION III: Engineering Problem 20. Calculate the root mean square radius of gyration for poly(styrene-block-hydrogenated) where the styrene block has a molar mass of 50,000 g/mol and the isoprene block has a mass of 40,000 g/mol. Assume the blocks are composed of C-C bonds with a length of 0.15 nm, and that the characteristic ratio for the styrene block is 5.0 and 4.2 for the isoprene block. (10 pts) SHOW ALL WORK BELOW 15 pts

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