Chemistry 824 Final Exam, Fall 1996



Chemistry 824 Final Exam, Fall 1996

Name:________________________________

This exam is worth a total of 80 points. Each question is worth 10 points. There are a total of 10 questions. Answer 8 of these. Clearly indicate which eight you want me to grade!!!!! In you explanations use text, diagrams, reactions, and equations as appropriate.

1. Clearly describe how you could initiate a polymerization so that all chains start growing simultaneously. How would this affect the molecular weight distribution of the resulting polymers.

2. The two polymerization initiators shown below have the indicated half lives. Which would give the highest molecular weight polymer at 60 degrees? Which would carry out the polymerization most quickly at this temperature. Clearly describe your reasoning.

3. Discuss the process of combustion of solids. With reference to this explanation, indicate how you could make a plastic non-flammable or less-flammable.

4. Compare and contrast bulk and solution polymerization methods. For each method, give its advantages and disadvantages and list specific examples of where it is used in the “real” world.

5. For the following two polymers. Discuss very briefly at least 5 ways they could be distinguised using instrumentation available at YSU.

6. Draw the structures of the polymers produced in the following reactions. Rank these polymers in order of solubility in water giving your reasoning. Rank these polymers in order of solubility in toluene giving your reasoning.

7. Draw the structures of polystyrene and copoly(styrene-divinylbenezene). Compare and contrast what would happen to them when they were added to toluene.

8. Draw the structures of the polymers produced in the following reactions. Predict which would be the most readily processed and which would be the most thermally stable giving detailed reasons.

9. For one of the polymer characterization techniques discussed in class and/or the class’s term papers (but not the one on which you did your term paper), describe: (a) the basic principles of how it operates, (b) what type of information it provides, and (c) what its advantages and disadvantages are for a small company.

10. Given the following model reaction as your starting point. Show the structures of two related silicon containing polymers that might be prepared similarly and predict how their properties might be related to those of polymers we have discussed in class.

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