slime by huangyuarong

VIEWS: 7 PAGES: 2

									                                                                                        MSanders/slime10
Name____________________________Date___________Pd_____

                                     SLIME Investigation!

                          What is a polymer?

                          A polymer is a large molecule which is composed of many repeating monomer
                          units. There are many types of polymers including inorganic polymers such
                          as glass or concrete, natural organic polymers like DNA or proteins and
                          synthetic organic polymers such as polystyrene or vulcanized rubber. We
                          are virtually surrounded by plastics and synthetic polymers in our clothes,
                          toys, foods, and vehicles.



What are the physical properties of a polymer?

A polymer's function and physical properties, such as strength or viscosity, depend on its final 3-
dimensional structure (straight chain or cross-linked) often called a matrix. Slime is a polymer. Slime
is a cross-linked polymer that is formed from the gelation of poly(vinyl alcohol) [PVA] with sodium
borate decahydrate (borax) in a water solvent.


The reaction is typically written as follows:

                        PVA + Na2B4O7·10 H2O                            Slime

How does the slime actually form?

Step 1-Solid Polyvinyl Alcohol (PVA) is dissolved in liquid water.

Picture:




Step 2- Solid sodium borate decahydrate (borax) is dissolved in water,
producing the tetraborate ion.

Step 3- The polyvinyl alcohol (Step 1) is cross-linked using borax (Step 2)

Picture:
Safety precautions:
   1) Wear safety glasses
   2) The borax and the PVA will burn the eyes. Hands should be washed at the end of the
      lab
   3) Keep the slime away from your clothes or cloth covered furniture as they may
      produce permanent stains
   4) Discard the slime in the trash, not down the drain, if it becomes moldy.


Procedure:
  1) Using a syringe, place 50.mL of 4% PVA solution into a disposable cup
  2) Add two drops of food coloring
  3) Stir with a wooden stick
  4) Using a syringe, add 5mL of saturated sodium borate solution into the cup with
     stirring.
  5) Store your slime in an airtight plastic bag.



Observations:

1) Observation of the PVA before the sodium borate is added:

2) Observation of the PVA after the sodium borate is added:

3) Observation of stretching the slime slowly:

4) Observation of stretching the slime rapidly:

5) Observation of letting the slime “pour” from one hand to another:

6) Observation of rolling the slime into long ropes:

7) Observation of the slime left out in the air overnight:


Did you know? There are a number of uses of the PVA polymer we are studying:

   1. They may be used in sheets to make bags to act as containers for pre-measured
      soap you simply throw into a washing machine.
   2. The PVA sheets may be made into larger bags to be used by hospitals as containers
      for the cotton cloth used in the operating rooms or to hold the bed linen or clothing
      of infected patients.

								
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