Polymers & Serendipity
Activities
Marcy Copeland, Yellow Medicine East High School, Granite Falls,
MN
Dan Larson, Anoka High School, Anoka, MN
Dan Morton, Roseville Area High School, Roseville, MN
These lab activities are designed to accompany lessons
in the role of serendipity in science. Students are
usually impressed that they can prepare these polymers
in a simple school lab:
To get students started, try this:
An Introduction to Polymers
This is a partial list of common items that
contain polymers.
Circle those that you have seen in the past seven days!
GARBAGE BAGS * FOAM CUPS * MILK JUGS *
TOOTHPASTE TUBES * SANDWICH BAGS * FAST FOOD CONTAINERS
* SHOE LACES * JUNK FOOD BAGS * 2-LITER BOTTLES * MOTOR
OIL BOTTLES * PLASTICWARE * SHAMPOO BOTTLES * SHOESTRING
TIPS * FOOD WRAP * DISPOSABLE RAZORS * MARGARINE TUBS *
DISPOSABLE DIAPERS * COFFEE STIRRERS * INSULATION * CAULKING
* SHRINK WRAP * SILLY STRING * SILLY PUTTY * SLIME * CELLOPHANE
TAPE * EPOXY GLUE * SUPERGLUE * DISH PANS * PLASTIC DISHES
AND CUPS * TEFLON COATING * COMBS * TOOTHBRUSH * COUNTERTOPS
* CARPET * TELEPHONE * FLOOR TILE * SYNTHETIC CLOTHING
* SHOE SOLES * PAINT * TIRES * WINDSHIELD * SHOE BOX *
DASHBOARD * FLOORMAT * VINYLTOP * BICYCLE HANDGRIPS * REFLECTORS
* VINYL WALL COVERING * SUNGLASSES * COMPACT * CONTACT
LENSES * HAIRSPRAY * LIPSTICK TUBES * RAINCOAT * PANTYHOSE
* UMBRELLA * RUBBER GLOVES * NERF BALL * FRISBEE * SNORKEL
* SWIM FINS * RACQUETBALL * TENNIS BALL * GUITAR STRINGS
* BALLOONS * RUBBER BAND * CREDIT CARDS * PORTABLE RADIO
* COMPUTERS * SAFETY GLASSES * FALSE TEETH * MUGS * LUNCH
TRAY * FLOWER POT * MICROWAVE COOKWARE * LAWN CHAIR * ASTROTURF
* VELCRO * FOOTBALL HELMET * HOCKEY PUCK * BUTTONS * ERASERS
* THREAD * WIG * SURFBOARDS * PARACHUTE * SAIL * CORVETTE
BODY * PLAYING CARDS * FLOOR WAX * RECORDS * AUDIO TAPES
* COMPUTER DISCS * CDS * TYPEWRITER RIBBON * FLEA COLLAR
* INDEX TABS * MODEL PLANES * JEWELRY * PACIFIER * BABY
BOTTLE * FOAM RUBBER * PHOTO FILM * PHOTOGRAPHS * PLASTIC
FLOWERS * MANNEQUINS * SCHOOL DESK * PROTRACTOR * RULER
* OVERHEAD TRANSPARENCIES * SLIDES * TEST TUBE BRUSH *
RUBBER TUBING
Can you name others?
PREPARATION OF NYLON 6-10
MATERIALS:
- 50 mL of 0.5 M hexamethylenediamine, H2N(CH2)6NH2*
- 0.5 M sodium hydroxide*
- 50 mL of 0.2 M sebacoyl chloride, ClCO(CH2)8COCl*
- Gloves
- 250-mL beaker
- forceps
- 2 stirring rods
- food-coloring dye (optional)
- phenolphthalein (optional)
*Kits containing these compounds already prepared can be ordered
from most chemical supply companies.
!! HAZARDS !!
Hexamethylenediamine and sebacoyl chloride are irritating
to
the skin, eyes, and respiratory system.
Sodium hydroxide is caustic.
Hexane is extremely flammable as well as producing an
irritating vapor. |
PROCEDURE:
- Wearing gloves and goggles, prepare the hexamethylenediamine
solution by dissolving 3.0 g of 1,6-diaminohexane and 1.0
g of NaOH in 50 mL of distilled water. (The hexamethylenediamine
can be dispensed by placing the reagent bottle in hot water
until sufficient solid has melted and can be decanted.
mp = 39-40oC)
- Prepare the sebacoyl chloride solution by dissolving
1.5-2.0 mL sebacoyl chloride in 50 mL hexane.
- Place the hexamethylenediamine solution in a 250-mL beaker.
Food coloring or phenolphathalein may be added to this
lower phase to enhance the visibility of the liquid interface.
- Slowly pour the sebacoyl chloride solution as a second
layer on top of the diamine solution, taking care to minimize
agitation at the interface.
- With forceps, grasp the polymer film that forms at the
interface of the two solutions and pull it carefully from
the center of the beaker.
- Wind the polymer thread on a stirring rod.
- Wash the polymer thoroughly with water or ethanol before
handling.
DISPOSAL:
Any remaining reactants should be mixed thoroughly to produce
nylon. The solid nylon should be washed before being discarded
in a solid waste container. Any remaining liquid should be
discarded in a solvent waste container or should be neutralized
with either sodium bisulfate (if basic) or sodium carbonate
(if acidic) and flushed down the drain with water.
Click here for the story of
the serendipitous discovery of nylon.
PRODUCTION OF CUPRAMMONIUM RAYON
MATERIALS:
- CuSO4.5H2O*
- NaOH
- Concentrated NH3 Solution
- 1.6 M H2SO4 (88.8 mL of concentrated H2SO4 solution diluted
to 1.00 L with distilled water)
- 11.0 cm filter paper*
*MODIFICATIONS/SUBSTITUTIONS:
- CuSO4.5H2O can be purchased as root killer at a garden
supply store.
- NaOH can be purchased as lye in grocery stores.
- Sulfuric acid is available from auto supply stores as
battery acid. This solution is 4.8 M.
- Paper towels could be substituted for the shredded filter
paper in this reaction.
EQUIPMENT:
- 250-mL Erlenmeyer flask
- 1000-mL beaker
- Syringe or bulb/pipette combination
- Funnel
- Filter paper
- Funnel support
- Magnetic stirrer (optional)
- Buchner funnel and filtering flask (optional)
!! HAZARDS !!
Avoid skin contact with all reagents.
> Use caution when making NaOH and H2SO4 solutions -- both are exothermic.
Avoid breathing NH3 vapors and work in a hood, if possible.
Goggles must be worn for this demonstration.
|
PROCEDURE:
- Dissolve 25.0 g of CuSO4.5H2O in 100 mL distilled water.
Heat the water to accelerate the dissolving process.
- Dissolve 8.0 g of NaOH in 200 mL of distilled water.
- Mix the cooled NaOH solution with the copper sulfate
solution. Collect the resultant gelatinous precipitate
of Cu(OH)2 by filtration. Wash the precipitate with three
10-mL portions of distilled water. If using 11.0 cm filter
paper, several filtrations will be required because of
the large amount of precipitate produced.
- Measure 70-mL concentrated NH3 (aq) into a 250-mL Erlenmeyer
flask. Shred four pieces of 11.0-cm filter paper. Add the
Cu(OH)2 precipitate carefully along with the filter paper
to this flask and stir. This should result in a deep purplish-blue
solution of tetraaminecopper (II) hydroxide, referred to
as Schweizer's reagent. Stopper the flask and stir periodically
for 24 hours. Use a magnetic stirrer, if available.
- Take up the contents of the 250-mL Erlenmeyer flask in
10-mL increments in a 10-mL or 50-mL syringe. Squeeze out
the contents into a 1000-mL beaker contained 300 mL of
1.6 M sulfuric acid. Be sure that the tip of the syringe
or pipette is under the surface of the acid. A crude 'thread'
should form.
- The clumps of threads can be washed free of the solution
to show the white color of rayon.
DISPOSAL:
Flush the ammonia solution and the sulfuric acid solution down
the drain with copious amounts of water. Dispose of rayon with
solid waste.
The chemical structure of the product
can be represented by the formula:
Click here for the story of
the serendipitous discovery of rayon.
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