Polymers

It is possible to modify the properties of many polymers by 3 generating crosslink such as these. You will experiment with crosslink the polymer in Elm's glue. A number of different processes are used to turn synthetic and natural polymers into useful objects. These include molding, extrusion, foaming and casting. In this experiment, you will use the technique of extrusion-blow molding in which a tube of polymer is blown up while in the molten state inside of a hollow mold. Almost all Throughout the experiment, you will test the various properties of the polymers that you synthesize and modify.Some polymers have exceptional properties and capabilities that can make them extremely useful to us. You will observe the property of one such polymer, sodium polymerase (the sodium salt of polysaccharide). CHI An NH O NH This polymer can absorb up to 800 times its own weight of water. The ionic portion of the macromolecule is directed toward the center of the structure. When water is added to dry sodium polymerase, the water molecules are drawn into the center of the polymer in an attempt to dilute the salt, and the polymer expands.It is very important that you record careful observations throughout the experiment. You will be asked to describe the appearances and properties of the various polymers in your lab report. 4 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 defensibly peroxide and shake the tube to mix. Caution! Defensibly 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 minut es. 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?Glottal Resin The following procedure must be carried out in a fume hood! Obtain a paper cup. Place 5 Goff ophthalmic anhy dride 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 our 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 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. 5 Modification of polymers Experiment on crosslink with Glue It is recommended that gloves not be worn when working with Elm's glue. It is easier to remove glue residue from your skin than from the gloves. Obtain a plastic cup and pour 15 ml of Elm's white g lue into it.Add 15 ml of water and stir well. Next, add 10 ml of saturated borax solution (sodium borate, Nabbing) and stir well. Remove the solid material and pull it off the stirrer. The material will be sticky for about one or two minutes. Pour any excess liquid left in the cup into the appropriate Laboratory Byproducts Jar. Rinse the cup with warm water. Perform another crosslink experiment using 1 5 L of glue and different amounts of water and borax (from 5 to 15 ml of borax and from O to 30 ml of water). Compare the properties of the two polymers (strength, bounce, stretchiness, etc. ).Observe the properties of at least two other students' polymers who used different amounts of water and borax in their second preparation. Record these observations. Polymer fabrication Polyethylene bottle Heat one end of a 10-15 CM piece of polyethylene tubing in a Bunsen burner flame. When the polymer is in the molten state, crimp the end with crucible tongs to seal it off?allow it to cool som ewhat before opening the tongs. Re-heat the tubing at the loosed end by passing it in and out of the flame until 1-2 inches of the tubing is in the molten state (looks transparent instead of opaque).Place the molten tubing into a small wide-mouth Jar or vial. Blow air into the open end of the tube so that it expands within the Jar. Let the expanded tubing cool in the Jar for about 2 minutes. Because the polymer is flexible, you should now be able to easily remove it from the â€Å"mold†. Show your polyethylene bottle to your TA. Polymer properties Supersaturates Weigh 1 Goff sodium polymerase and place it in a 150 ml beaker. Add 50 ml of water to the beaker from a graduated cylinder. Record your observations. Add another 50 ml of water to the beaker. Record your observations.