Marva Anyanwu - Wendell E. Green 



World Of Plastics And Polymers
 
Marva Anyanwu                      Wendell E. Green 
                                   1150 West 96th Street                   
                                   CHICAGO IL 60643
                                   (773) 535-2575 

Objective(s):

Grade Levels 7-12  (Can be adapted for grades 4-6).

1.  To show plastics are polymers (giant molecule) containing carbon atoms 
    forming long chains. 
2.  To differentiate and identify materials as synthetic or natural polymers.
3.  To examine and observe characteristics of different materials that are
    polymers.

Materials Needed:
    
    Materials are listed with each activity.

Strategy/ies:

 Introduction:

    Display various grades of plastics and have students identify them.  Spray
    string confetti (toy store) around the room, have the students pick up the 
    string and feel and describe the texture.  Present the new vocabulary in a 
    simple manner. 

Activity 1:

    Materials: 500mL (2 cups) of whole milk, 150mL (2/3 cup) of vinegar, food 
    coloring, a strainer with fairly small openings, a small saucepan, a mixing
    spoon, a stove.

    Procedure:

    1.  Measure the milk and place in the saucepan.  Slowly warm the milk, but
        do not heat it even close to the boiling point.
    2.  Add several drops of food coloring to the milk so the object you form 
        will be colored.
        Remove the pan from the stove.  Slowly add the vinegar into the milk
        in the pan.
    3.  Use your stainer to separate the solid that has formed from the liquid 
        in the pan.  This solid is a plastic.
    4.  After the liquid has drained through the strainer, pour a little water
        through the strainer to rinse the plastic.
    5.  Form the plastic into a ball and set it on a paper towel for a few 
        minutes to remove some of the excess moisture.
    6.  You should then be able to form the plastic into the object of your
        choice.
    7.  When you have finished shaping your object, set it aside for a week to
        dry.  The object will probably shrink a little as it dries out.
    Hint:  Think of environmental concerns.

Activity 2:   A Polymer

    Materials:
     
        Elmer's white glue, small disposable plastic cup, saturated borax 
        solution.

     Procedure:
   
     1.  Place 5 mL of white Elmer's glue in a small disposable plastic
         cup.
     2.  Add saturated borax solution (4g sodium borate dissolved in 96g
         water-wt-volume) dropwise as you stir.  About 1 mL  of borax
         will be required.  A sticky ball will form.
     3.  Remove the sticky ball from the cup and rinse it thoroughly with
         tap water.
     4.  Roll it into a ball.  You can bounce it, when allowed to stand it
         will flow.
     5.  If the consistency of you polymer is not thick enough to form a ball
         you may need to add more borate solution.
     Note:  The borax is cross linking the polymer chains in the white glue.

Activity 3:  Plastics  

     Procedure:

     1.  Listening skill utilized.  Teacher will read the instructions.
     2.  Place a small amount of acetone (very inflammable) in a 300mL beaker.
     3.  In the beaker place a small styrofoam cup containing a weight.  It
         will slowly dissolve in the acetone.
     4.  Add to the beaker containing the acetone and styrofoam cup a large 
         volume of foam peanuts used for packing fragile objects.
     5.  After the two have dissolved, allow the remaining acetone to 
         evaporate.  A disc of polystyrene will remain in the bottom of the
         beaker. 

Performance Assessment:

     1.  Using illustrations students should be able to identify the different 
         kinds of chains carbon atoms form when bonded together during 
         polymerization.
     2.  Identify structural models of common organic compounds.
     3.  Describe the difference between a polymer and a monomer.
     4.  Classify substances as natural or synthetic polymers.  
     5.  To make a model of a common organic compound such as polyethylene 
         polymer from which many products are made.  Use any two types of
         ball-shaped candies or fruit with toothpicks. 

Conclusions:

    Many of the products or substances in our society are made by a process
    called polymerization.  It is a chemical process where small molecules
    link up together to form large molecule chains.  In polymerization when the
    structure in the organic compound is changed, the arrangement confers 
    different chemical properties which enable so many polymer products to be
    produced with diversity.  

References:

     Price, Jack. Smith, Richard G., Smoot, Robert C.  Chemistry A Modern
     Course.  Teacher Edition.  Ohio: Merrill Publishing Company, 1990 
     Aldridge, Bill. Aiuto, Russell. Ballinger, Jack. Sydner, Susan.
     Science Interactions Course 3. Teacher Edition.  Ohio:  Glencoe 1993