Transcript Silicone Super Ball

Synthesizing a Silicate
Chain to Form Superballs
Question
What does combining sodium silicate and
ethyl alcohol create?
How does your bouncy ball bounce?
Synthesizing Inorganic Polymer
 In this lab experiment, you will
synthesize an inorganic polymer
based on silicon.
 Inorganic polymers are polymers with a
non-carbon backbone. Silicon is an
element directly below carbon, yet the
chemistry of carbon and silicon are very
different.
Silicones & Polymers
Silicones are largely inert compounds with a wide variety of
forms and uses. Typically heat-resistant, nonstick, and
rubberlike.
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They are frequently used in:
Cookware
Medical applications
Sealants
Lubricants
Insulation
Silicones are polymers that include silicon
together with carbon, hydrogen, oxygen,
and sometimes other chemical elements.
Polymers
(Greek poly means many and (meros), meaning "part”)
 A polymer is a large molecule (macromolecule)
composed of repeating structural units connected
by covalent chemical bonds.
 Polymerization – joining of many small molecules
to form a large molecule.
 Well-known examples of polymers include
plastics, DNA, and proteins.
Discussion
 The super ball is a variation of a simple
silicone. Silicone is the term used to
describe any organosilicon oxide
polymer in which the structural unit is
usually: R is an organic, usually a
methyl group.
Sodium silicate solution is produced by fusing
sand (SiO2)n and soda ash (Na2CO3) in a
furnace at about 1300 oC.
The final product, Na2O (SiO2)n is also called
water glass.
The reaction with ethyl alcohol produces a
super ball which is most likely a silicone
elastomer where the R is (- O - CH 2CH3).
Elastomer
Elastomer is a big fancy word, and all it means is
"rubber". Some polymers which are elastomers
include polyisoprene or natural rubber,
polybutadiene, polyisobutylene, and polyurethanes.
What makes elastomers special is the fact that they
Bounce and can be stretched to many times their
original length, and can bounce back into their
original shape without permanent deformation.
Materials Needed
20 mL Sodium silicate solution
10-mL Ethyl alcohol, CH3CH2OH, 95%,
wooden splint
small paper or plastic cup
Caution: This activity requires the use of hazardous components
and/or has the potential for hazardous reactions. Please review the
Safety Precautions section on the following page and relevant
Material Safety Data Sheets before beginning this activity.
Procedure
1. Measure out and add 20 mL of sodium silicate solution to
the paper cup.
2. Measure out 10 mL of 95% ethyl alcohol and add it to the
paper cup.
3. Stir the mixture with the wooden splint in a regular circular
motion.
4. As the mixture solidifies, squeeze out the liquid with gloved
hands; place the solid in the palm of your hand and form the
solid into a ball.
5. As you form the ball, continue to gently press out the
excess liquid.
6. Bounce the ball and measure the height of the bounce!
Measure the height that your
superball bounced to.
Trials
Student
Name
Height
(cm)
Trial 1
Height
(cm)
Trial 2
Height
(cm)
Trial 3
Height
(cm)
Average
Tips
 Adjust the amount of alcohol used (anywhere from
5 to 15 mL) and observe the differences between
the superballs.
 The superballs will vary in how brittle they are.
 The silicone super ball is brittle and may crumble.
It may be reformed by pressing it between the
palms of your hands.
 The super ball should be stored in a closed or
airtight container when not in use.
Safety Precautions
 Ethyl alcohol is a dangerous fire risk; it is
flammable. The addition of denaturant makes ethyl
alcohol toxic by ingestion.
 Sodium silicate solution is very alkaline, it is a
skin irritant.
 Wear chemical splash goggles, chemical-resistant
gloves, and a chemical-resistant apron.
Polymers
• Polymers – large chainlike molecules made from many
small molecules called monomers
 Simplest polymer – polyethylene
 Polyethylene results from addition polymerization.
Polymers
 Condensation polymerization – a small molecule (often
water) is released for each addition of a monomer to the
polymer chain
 Nylon (co-polymer) and as you can see carbon based.
• Copolymer – 2 different types of monomers combine to
form the chain
Sodium Silicate polymer
 When sodium silicate and ethyl alcohol are put together,
the silicate particles begin to link up with each other to
form long chains as the ethyl groups (sometimes shown
as "R") replace oxygen atoms in the silicate ion. (Some
become cross-linked between chains.)
Water molecules are by-products of the formation of the
polymerization bond.
 The large molecule is a solid.