Unknown Polymer Identification prepared by Kenneth Kauffman

Background:

You currently work for a multi-division corporation in their maintenance engineering department. On one of the specialty machines utilized in the processing division, a small plastic piece has failed. You've been asked to replace it. Kauffman Ltd. manufactured the original part. However, the company has since gone out of business and you have been unsuccessful in finding the specifications for the part in your company's files.

Your supervisor and you agree that the part is most likely one of five very common polymers:

polyethylene

polypropylene

polystyrene

polycarbonate

poly(vinyl chloride)

Since your company produces each of these polymers, you have samples of each on hand. You also have access to an R&D lab with some basic equipment, which includes some of the following equipment (prior to the experiment, your teaching assistant will tell you which equipment):

· a heater at 140'C

· a heater at 220'C

· a flame source

· standard solutions of density 1.00 g/cm 3

· standard solutions of density 1.05 g/cm 3

· insulated cups

· thermometers

· an ice bath

· a squirt bottle of acetone

· samples for hardness testing

· samples for testing the tensile strength

Procedure:

Using your samples of the known polymers, develop a series of tests using the above equipment which will conclusively identify a given sample of polymer. After you have done the preliminary tests and you know the results of each test, develop a flow sheet which will allow you to conclusively identify the polymer. Your final flow sheet should look similar to the basic outline shown below (not necessarily exactly like this):

UNKNOWNS

Prelab:

Your prelab should consist of physical and chemical properties which will allow you to predict the results for each test you do before you conduct each test. You should also have experimental procedures written for each test you will do BEFORE you show up. You have the equipment available. Now, you need to determine how to do the tests.

Report:

For this experiment, the most important components of the report (by far) will be your background section, your experimental procedures, and the flow chart which you develop. The background section should contain descriptions of each of the key properties you utilized, key equations which were manipulated so you could utilize the data you collected, and background information on common uses of each of the polymers.

Polymer Identification Lab:

Objective:

Commonly, it is desirable to know what type of polymer is present in a given situation. Often, the easiest way to do this is by conducting some basic observational tests. Through this experiment, you will develop a series of tests which will allow you to distinguish between various polymers.

Procedure:

In the first part of the lab, you will be given access to various known standards of polymers. Using these standards, you are to design a series of tests which you can carry out to determine the composition of an unknown. The unknown may contain any single polymer or a mixture of the two.

You may use anything in the lab that you desire for the experiments so long as it does not pose a health hazard to yourself or the other people working in the lab. Before using any chemicals or equipment, consult with your T.A. to ensure that no hazard exists.

Report:

You should cover in your report how you came upon the procedure you developed, how your procedure works, and what the definitive tests are. Also discuss the properties of each polymer which you measured. In addition, find relevant data on the approximate usage of each of the polymers tested.

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