Polymer

Sherrie L. Birts               Teacher Academy of Mathematics and Science
                               10 West 35th Street
                               Chicago IL 60616
                               (312)808-0100

Objective:

These lessons can be adapted and made appropriate for grade 6-12.
Students will be able to:  1) understand the meaning of a polymer, 2) observe 
and compare the properties of a polymer, 3) describe the relationship between 
smaller individual molecules joined together to form the larger polymer 
molecules, 4) explore common uses of polymers, 5) learn safety and experimental 
techniques.

Material Needed:

Material per student
Experiment A: 
1 polystyrene foam (recycled cup is very cost effective)
1 glass petri dish (aluminum pan can be substituted)
paper towel
acetone

Experiment B:
paper towel or newspaper
3oz. paper cup with 15ml of monomer A
3oz. paper cup with 15ml of monomer B
two plastic bags or gloves
wooden splint

Experiment C: 
1 bottle New Elmer's School Glue Gel
4% borax solution
Gladloc plastic bag
warm tap water

Strategy:

Experiment A:  Observation of Plastics:  What's in the Cup?
Using the 25ml graduated cylinder, measure out 10ml of acetone and pour it into 
the petri dish.
Take an ordinary, foam, polystyrene coffee cup and place the polystyrene cup 
into the acetone in the petri dish.  Describe what you see happening.
Remove the lump of material from the acetone with your fingers.  Examine the 
polymer now and describe its appearance and properties.
Form the polymer into some interesting shape (ball, donut, cube) and allow it to 
dry on your lab bench or at home.  Write down what you observe the next day 
about the polymer.

Experiment B:  Polyurethane Foam
Put gloves on and remind the students to keep gloves on at all times when 
working with the polyurethane foam.
Spread the paper towel on the bench top.  The bench top should remain covered 
while working with the monomers.
Add 3-5 drops of food coloring to one of the monomers, then mix it up thoroughly 
with the wooden splint.
Pour the other liquid into the cup.  Mix the two liquids thoroughly with the 
wood splint for at least 2 minutes.  Continue to stir until the volume of the 
mixture begins to increase.  At this point, stop stirring the mixture and remove 
the splint.
DO NOT TOUCH THE FOAM!  It must not be handled until it is completely set, since 
it may contain unreacted materials.  It will be ready to handle after 24 hours. 
                                                                             
Experiment C:  A Fun Polymer:  Slime                                                               
Mix 3 parts tap water with 1 part glue gel (For instance, use 10ml glue and 30 
ml water) in the GladLoc plastic bag.  Stir until completely dissolved.  This 
may take 2-3 minutes.  Warm water works faster.
Add 1-2 drops of food color, if desired, into the glue-water mixture.
Add 1 teaspoon (5ml) of 4% borax solution and stir until the slime adheres to 
the stick in a large blob.  You are now ready to play with it and observe its 
properties.
CAUTION: Keep in a plastic bag when not using it.  Keep it off of clothes, 
upholstered furniture and varnished wood.

Performance Assessment:

The students should be able to:
1. Build a polymer model (form a hat or mushroom) using polyurethane foam.  They 
will decorate their model with food color, buttons, or any craft materials.
2. Form a shape with the polystyrene cup and observe the shape after a 24 hours 
period.
The students work should be displayed and graded.
3. Have the students complete a worksheet identifying every polymer in their 
home.

Reference:

Moore, John W. (1992).  Crystal Growing and Polymers.  Chem Camp Handbook:  
   Institute for Chemical Education, University of Wisconsin-Madison.

Sherman, Marie.  Making Gel-Gluep From Elmer's School Glue Gel. Ursuline
   Academy, St. Louis.