Procedure
Record detailed observations throughout the experiment.
Polymer synthesis
Addition polymer—Polystyrene
Place 20 drops of styrene into a disposable 13 x 100 mm test tube (provided by
your TA). Caution! Styrene is a flammable liquid! Keep styrene away from all
Bunsen burner flames. It is also a suspected carcinogen. Wear gloves! Using a
wooden or plastic utensil, add a few grains of dibenzoyl peroxide and shake the tube to
mix. Caution! Dibenzoyl peroxide is explosive when heated. Use only a few grains!
Label the test tube with your name, and place it in a sand bath that has been set up
by your instructor. Allow the solution to heat for 90 minutes. You may proceed with the
rest of the experiment as it heats.
When the material in the test tube has turned slightly yellow, remove the test tube
from the sand bath and cool it on ice. Try to shake the polymer out of the test tube. If it
has not separated from the glass sufficiently to do this, you may wrap the test tube in a
cloth towel and carefully break it so that the polymer can be removed. Wear gloves when
doing this! Describe the appearance and properties of your polymer.
Test the solubility of the polymer by grinding a few chunks in a mortar and pestle
and placing the powder in two test tubes. Add water to one of the test tubes and acetone
to the other test tube. Record your observations. Dispose of the acetone mixture in the
appropriate Laboratory Byproducts Jar.
Discard the polystyrene in the appropriate Laboratory Byproducts Jar.
Condensation Polymer—Glyptal Resin
The following procedure must be carried out in a fume hood!
Obtain a paper cup. Place 5 g of phthalic anhydride and 0.25 g of sodium acetate
in a disposable 18 x 150 mm test tube (provided by your TA). Add 2 mL of glycerol.
Using your test tube clamp, carefully heat the mixture over a Bunsen burner flame (see
TECH I.D). Heat the top of the contents first and work toward the bottom as the mixture
melts. Move the test tube in and out of the flame as you do this. Note when the mixture
begins to boil and then continue to heat for 3 to 4 minutes. The solution should turn
yellow in color. If it begins to turn brown, stop heating.
Pour the solution into the paper cup. Allow the solution to thoroughly cool, then
tear off the cup to recover your polymer. Dispose of the test tube in glass waste.
Describe the appearance and properties of your polymer.
Test the solubility of the polymer as you did for polystyrene.