Section 2.2: Synthetic Addition Polymers
Tutorial 1 Practice, page 87
1. (a) Draw three structural diagrams of C2H2Br2. Show each molecule with the doublebonded carbon atoms all in a line, and place other atoms below or above that line.
Next, connect the monomers with single bonds to form a chain. Remove the double
bonds within the monomer, replacing them with single bonds so that each carbon atom
has exactly four bonds. Add lines at each end to indicate that this is just one segment of
the longer polymer molecule.
The name of this polymer is polydibromoethene.
(b) Draw three structural diagrams of CH3CH2CH=CHCH2CH3. Show each molecule
with the double-bonded carbon atoms all in a line, and place other atoms below or above
that line.
Next, connect the monomers with single bonds to form a chain. Remove the double
bonds within the monomer, replacing them with single bonds so that each carbon atom
has exactly four bonds. Add lines at each end to indicate that this is just one segment of
the longer polymer molecule.
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Chapter 2: Polymers
2.2-1
The name of this polymer is polyhex-3-ene.
(c) Draw three structural diagrams of CHCl=CHCH3. Show each molecule with the
double-bonded carbon atoms all in a line, and place other atoms below or above that line.
Next, connect the monomers with single bonds to form a chain. Remove the double
bonds within the monomer, replacing them with single bonds so that each carbon atom
has exactly four bonds. Add lines at each end to indicate that this is just one segment of
the longer polymer molecule.
The name of this polymer is poly-1-chloropropene.
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Chapter 2: Polymers
2.2-2
2. Draw three structural diagrams of CH2=CHCN. Use Table 1.
The name of this monomer is cyanoethene. The monomer is more commonly known as
acrylonitrile.
Next, connect the monomers with single bonds to form a chain. Remove the double
bonds within the monomer, replacing them with single bonds so that each carbon atom
has exactly four bonds.
Add lines at each end to indicate that this is just one segment of the longer polymer
molecule.
3. Identify the repeating unit.
Draw the monomer. Replace the single bond between two carbons with a double bond.
The name of this monomer is bromoethene.
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Chapter 2: Polymers
2.2-3
Research This: Paying with Plastic, page 88
Answers may vary. Sample answers:
A. Answers will vary. Sample answer:
Polymer-based dollar bills
Cotton-based dollar bills
Advantages
Disadvantages
Advantages
Disadvantages
–more durable
–stick together
–lighter to carry
–last only a few
–harder to
when wet
than coins
years
counterfeit
–hard to fold
–easy to counterfeit
–harder to tear
using scanners and
–resistant to folding
photocopiers
–resistant to dirt
–waterproof
–easier to machine
process
–can be shredded
–can be recycled
after use
B. Answers will vary. Sample answer:
Polymer bills include features such as latent images, intaglio, micro-printing, offset and
letterpress printing, intricate background patterns, watermarks, shadow images, and
security threads. Their key security feature is the transparent window, which contains an
optically variable device (OVD) and allows easy identification of an authentic note.
C. Anti-counterfeiting technologies are successful at first, but after a while, counterfeiters
find a way of mimicking anti-counterfeiting features; so new anti-counterfeiting
technologies and features need to be continually developed. There is less need to apply
this technology to coins because coins are made of metal, which is expensive and heavy,
and also coins are worth less than bills are.
Mini Investigation: Guar Gum Slime, page 92
Answers may vary. Sample answers:
A. When I first started stirring the mixture, the mixture began to slowly thicken.
B. After stirring for a few minutes, the mixture formed a gel-like semi-solid.
C. The slime pours through my fingers, but hardens if I hit it forcefully. The properties
depend on the force with which the slime is handled.
D. Guar gum itself includes long hydrocarbon chains. When these long molecules are in
water they tend to get somewhat tangled, forming a gummy substance. When sodium
borate is added, the hydroxyl groups react with the hydrogen atoms on the guar gum
chains, causing the long molecules to bind together more tightly, which results in the
observed slimy substance.
E. Answers may vary. Answers should indicate that the price of processed food may rise
as the supply of guar gum available for food production decreases. Students may discuss
negative implications of this, such as the reduced ability of some people to afford food.
They may also discuss potential positive implications, such as the increased cost of
processed food causing more people to buy unprocessed food, which could have longterm health benefits for them and for society, and also could decrease society’s health
care costs.
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Chapter 2: Polymers
2.2-4
Section 2.2 Questions, page 93
1. Identify the repeating unit.
Draw the monomer. Replace the single bond between two carbons with a double bond.
The monomer is chlorotrifluoroethene.
2. (a) Identify the repeating unit.
Draw the monomer. Replace the single bond between two carbons with a double bond.
The monomer is fluoroethene, C2H3F.
(b) Identify the repeating unit.
Draw the monomer. Replace the single bond between two carbons with a double bond.
The monomer is trans-1-bromo-2-chloroethene, C2H2BrCl.
(c) Identify the repeating unit.
Draw the monomer. Replace the single bond between two carbons with a double bond.
The monomer is phenylethene, C6H5CH=CH2.
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Chapter 2: Polymers
2.2-5
3. Draw three structural diagrams of methyl cyanoacrylate.
Next, connect the monomers with single bonds to form a chain. Remove the double
bonds within the monomer, replacing them with single bonds so that each carbon atom
has exactly four bonds. Add lines at each end to indicate that this is just one segment of
the longer polymer molecule.
4. Cross-links occur when chemical bonds form between separate polymer strands in two
or three dimensions. The more cross-links a polymer has, the more rigid and inflexible it
is.
5. (a) 1,4-divinylbenzene
(b) 1,4-divinylbenzene has two double bonds outside the benzene ring, so it can form
cross-links with other 1,4-divinylbenzene monomers or with styrene monomers, making
the copolymer more rigid.
6. Answers will vary. Answers may include the following information:
Scientists at the University of Southern Mississippi have invented polymers that are selfrepairing. They are made of polyurethane, which is scratch resistant. Oxetane and
chitosan are added to the polyurethane layer to protect it from scratches. When the
polyurethane is scratched, oxetane—which is an unstable ring consisting of an oxygen
atom and three carbon atoms—opens up, forming two ends that are reactive. When
chitosan is exposed to UV light, it binds with the reactive oxetane ends, thereby filling
the scratch.
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Chapter 2: Polymers
2.2-6
7. (a) Answers will vary. Sample answer:
Plastic
Plastic polymer type
identification
code
1
polyethene terephthalate (PET)
2
high-density polyethene (HDPE)
3
polyvinyl chloride (PVC)
4
5
low-density polyethene (LDPE)
polypropene (PP)
6
7
polystyrene (PS)
other (polycarbonate or ABS)
Use
water bottles, peanut butter jars
water pipes, grocery bags
rigid water pipes, electrical
cable insulation
squeezable bottles
yogurt containers, margarine
tubs
disposable cups, egg cartons
CDs, prescription glasses, lenses
(b) Answers may vary. Sample answer: Currently, the City of Toronto cannot recycle the
following items because there is no market for them: clear plastic “clamshells,” plastic
drinking cups, lids, straws, clear and opaque entrée and takeout food containers, lids,
plastic blister packs, toys, cassettes, CDs and DVDs, plastic pails, plastic paint pails (with
metal handles), and plastic over-wrap on pop or water cartons, toilet paper, and paper
towels.
(c) Plastic garbage bags can take from 20 to 1000 years to decompose in a landfill site.
(d) Things that I can do to reduce the environmental impact of plastics is to take my own
reusable shopping bags when I go shopping, buy in bulk to reduce the amount of
packaging, avoid buying items with heavy plastic packaging, buy only what I need and
will use, reuse as much as possible, and recycle what I can’t reuse.
8. (a) Polystyrene is useful for packaging because it can be foamed and molded into any
shape, and has insulating and damping properties.
(b) Alternative biodegradable packaging materials are biodegradable resin and BioFoam.
(c)
Polystyrene
Biodegradable resin
BioFoam
–synthetic polymer
–made from sugar cane
–made from polylactic
–not biodegradable
–biodegradable
acid, a by-product of sugar
–made from petroleum
–used as loose fill
cane processing
packaging material
–can biodegrade under
–no harmful chemicals
certain conditions
used in manufacturing
–can also be used as
insulation instead of
polystyrene
(d) Answers may vary. Sample answer: Of the three options, BioFoam is probably the
best because it is as versatile as polystyrene but can biodegrade under certain conditions.
It is likely more expensive than polystyrene, however, because it is not produced on the
same scale.
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Chapter 2: Polymers
2.2-7