Theme: Our Earth Resources
Learning and Teaching Activities
Preparation of nylon / Preparation of perspex
Teaching Tips
Experiments provide the opportunity for students to get the first-hand information and carry
out scientific investigation. Take precautions during practical and remind students to follow
instructions.
Objective: Understand the chemistry principle of polymerisation to make useful products.
Preparation of Nylon
Introduction
Nylon is an important material for home furnishings, apparel, carpet fibres and fishing line.
In this experiment, a polymerisation reaction performed to prepare Nylon-6,10 under simple
laboratory conditions, the decanedioyl dichloride is used to react with 1,6 – Hexanediamine.
O
O
C l C(CH2)4C Cl
hexanedioyl dichloride
O
+
H2N(CH2)6NH2
1,6 – Hexanediamine
O
Cl C(CH2)4C HN (CH2)6NH H
Nylon –6,6
+
HCl
Hydrogen chloride
Safety precaution
1. The experiment should be carried out inside a fume hood or in a well-ventilated area as
the gaseous hydrogen chloride is corrosive and irritating.
2. Labcoat and experimental gloves should be worn in the experiment.
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3. Ethanol is volatile and flammable. Store at cool and dark places. Avoid direct exposure to
sunlight.
4. The reagents of nylon could be stored for 2 weeks only. Purchase fresh chemicals for use.
Materials
1.1 g crystalline 1,6-hexanediamine 2.0 g sodium carbonate
1mL
hexanedioyl 50 mL dichloromethane in
dichloride
50 mL 50% ethanol
Watch glass
Glass dropper
100mL beaker
Glass rod
3 100mL beaker
Procedures
1.
Measure 1 mL of hexanedioyl dichloride into a 100-mL beaker containing 50 mL of
dichloromethane.
2.
Dissolve 1.1 g of crystalline 1,6-hexanediamine and 2.0 g of sodium carbonate in 50 mL
of water in a 100 mL beaker.
3.
Slowly transfer the 1,6-hexanediamine solution to the beaker containing hexanedioyl
dichloride solution with the aid of a glass rod.
4.
A film of polymer will form immediately at the interface of the two solutions. Use a
glass rod to pull the centre of the polymer film out slowly and spread it on a watch glass.
5.
Place the watch glass in a fumed hood for 10 minutes to evaporate the reactants on
nylon.
6.
Wash the nylon by submerging the glass plate in a beaker of 50% ethanol.
References
1. Gilbert, J.C. & Martin, S.F. (1994) 一 Experimental Organic Chemistry. A Miniscale &
Microscale Approach, 2nd Ed., Saunders College Publishing.
2. 香港特別行政區教育署 (2002) 科學實驗室安全手冊.
A(E)-T1-7-2
Preparation of Perspex
Introduction
The polymer Perspex is formed by polymerisation, obtaining by heating the monomer methyl
2 – methylpropenoate at about 60ºC in the presence of lauroyl peroxide.
Safety precaution
Labcoat and experimental gloves should be worn in the experiment.
Be careful of any spillage of broken glass in the later part of the experiment.
Materials
Lauroyl peroxide
5mL methyl 2 - methylpropenoate
Spatula
Thermometer
Timer
Forceps
Hammer
Test tube
250mL beaker
Tripod and gauze
Bunsen burner
Old newspaper
Procedures
1.
Fill a 250 mL beaker with about 180 mL of tap water; place the beaker on tripod and use
the Bunsen burner to heat the water to about 60OC.
2.
Add 5 mL methyl 2 – methylpropenoate to a dry test tube.
3.
Add 1 spatula of lauroyl peroxide to the test tube, swirl the tube to dissolve the solid.
4.
Immerse the test tube in the hot water bath (prepared at step 1) at about 60OC. Switch
on the timer. (Remember to keep the water bath temperature by controlling the flame)
5.
Every 10 minutes, take out the tube and examine its contents.
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6.
Continue to heat the liquid until it solidifies (Put back the tube into water bath if not
solidifies)
7.
Take out the test tube when the liquid solidifies. Record the time required for product
formation.
8.
Wrap the tube with newspaper and break it carefully with a hammer.
9.
Carefully take away broken glass pieces sticking to the solid product.
Observation
Discussion
1.
What happens to the liquid when heated?
2.
Briefly describe the product formed.
3.
How long does the polymerization take?
4.
State one precaution to be taken for this experiment.
5.
State one use of the polymer produced.
References
1. Gilbert, J.C. & Martin, S.F. (1994) 一 Experimental Organic Chemistry. A Miniscale &
Microscale Approach, 2nd Ed., Saunders College Publishing.
2. 香港特別行政區教育署 (2002) 科學實驗室安全手冊.
A(E)-T1-7-4
Suggested answers (Accept alternate and correct answer)
1.
What happens to the liquid when heated?
It become thicker and thicker (solidifies).
2.
Briefly describe the product formed.
A colorless, transparent solid formed.
3.
How long does the polymerization take?
About 1 hour. The answer varies, depending on the amount of lauroyl peroxide added
and the temperature.
4. State one precaution to be taken for this experiment.
Be awake of any accident. Perform the experiment in a well-ventilated room. Make sure that
air is pumped out of the hood during the experiment.
5. State one use of the polymer produced.
Ribbon, strings, etc.
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