Deck 16: Organic Polymer Chemistry

Question 1

Which polymers will be strongest?

A) PET 0% crystallinity
B) PET 20% crystallinity
C) PET 35% crystallinity
D) PET 55% crystallinity

Answer 1

PET 55% crystallinity

Question 2

Which polymers will be brittle at 0° C?
I. PVC, Tg = 83° C
II. PVA, Tg = 200° C
III. teflon, Tg = -80° C
IV. polypropylene, Tg = -100° C

A) III, IV
B) II, III
C) I, II
D) II, IV

Answer 2

I, II

Question 3

What is characteristic of the process of Step-Growth Polymerization?
I. In the beginning of the polymerization process, there are many oligomers (an oligomer is made from a few monomers, its chain length is short).
II. High macromolecular weights are only reached at the very end of the polymerization process.
III. If two bifunctional monomers (e.g. diamine and dicarboxylic acid) are used, slight deviations from 1:1 stoichiometry will prevent high macromolecular weights at the end of the polymerization process.
IV. Polymer chains can grow individually to high macromolecular weight at any time during the polymerization process.

A) I and II
B) II and III
C) I, II and III
D) II and IV

Answer 3

I, II and III

Question 4

Which polymers are correctly classified?

A) I, III
B) II, III
C) III, IV
D) II, IV

Question 5

Which characteristics are found in polymers with low degrees of crystallinity?
I. large molecular side groups
II. high Tm
III. strong intermolecular forces
IV. elasticity

A) I, III
B) II, III
C) III, IV
D) I, IV

Question 6

What small molecules can be released during Step-Growth-Polymerization?
I. H₂O
II. NH₃
III. methanol
IV. none

A) I
B) II, III
C) I, III
D) IV

Question 7

Which of the following are typical polymer architectures?
I. linear
II. tetrahedral
III. star
IV. ladder
V. forked

A) II, III, IV
B) III, IV, V
C) I, III, IV
D) I, II, IV

Question 8

Which characteristics are found in polymers with high degrees of crystallinity?
I. regular, compact structures
II. high Tm
III. weak intermolecular forces
IV. elasticity

A) I, III
B) I, II
C) III, IV
D) II, IV

Question 9

Which pair of compounds would react to form the polymer shown?

A) I
B) II
C) III
D) IV

Question 10

Which polymers are step-growth polymers?
I. Polyamides (e.g.Kevlar)
II. Polyesters (e.g.Mylar)
III. PVC
IV. PMMA (e.g. Lucite)

A) I, II
B) II, III
C) I, IV
D) III, IV

Question 11

Which terms are matched correctly with their definitions?
I. Crystalline domain - order regions in the solid state of a polymer.
II. Amorphous domain - disordered regions in the solid state of a polymer.
III. Melt transition temperature - temperature at which a polymer undergoes the transition from
Hard to rubbery state.
IV. Glass transition temperature - temperature at which glass polymers melt.

A) II, III
B) III, IV
C) I, IV
D) I, II

Question 12

Which pair of compounds would react to form the polymer shown?

A) I
B) II
C) III
D) IV

Question 13

Which classification best describes the mechanism of the synthesis of polyamides via step growth polymerization?

A) nucleophilic acyl addition
B) nucleophilic acyl substitution
C) electrophilic addition
D) radical substitution

Question 14

Which pair of compounds would react to form the polymer shown under appropriate reaction conditions?

A) I
B) II
C) III
D) IV

Question 15

Which polymers are correctly classified?

A) II, III
B) III, IV
C) I, IV
D) I, II

Question 16

Which terms are correctly matched to their definitions?
I. Plastic - a long chain molecule synthesized by linking together many single parts.
II. Polymer - can be molded when hot and retains its shape when cooled.
III. Thermoplastic - can be molded when hot and retains its shape when cooled.
IV. Thermosetting plastic - can be molded when first prepared, but hardens irreversibly when
Cooled.

A) III, IV
B) II, III
C) I, II
D) I, IV

Question 17

Why can any nylon-polymer not be used as an insulator in lead/sulfuric acid batteries?

A) PbO₂ would oxidize the polymer.
B) Aqueous H₂SO₄ would hydrolyze the amide-bonds.
C) Aqueous H₂SO₄ would dissolve the polymer.
D) Pb would reduce nylon to a polyamine.

Question 18

Which polymers will be the most elastic?

A) PET 0% crystallinity
B) PET 20% crystallinity
C) PET 35% crystallinity
D) PET 55% crystallinity

Question 19

Which polymers will be elastic at 0° C?
I. PVC, Tg = 83° C
II. PVA, Tg = 200° C
III. teflon, Tg = -80° C
IV. polypropylene, Tg = -100° C

A) III, IV
B) II, III
C) I, II
D) II, IV

Question 20

Which polymers are step-growth polymers?
I. nylon
II. HDPE
III. Teflon
IV. PET

A) I, II
B) II, III
C) I, IV
D) III, IV

Question 21

Which polymers are correctly matched to their primary use?
I. Kevlar and containers
II. Polymethylmethacrylate and Plexiglas
III. Polytetrafluoroethylene and nonstick coatings
IV. PET and bulletproof vests

A) I, III
B) II, III
C) II, IV
D) III, IV

Question 22

Before recycling, plastics are sorted according to their resin identification code, which was developed by the Society of the Plastics Industry in 1988. Presorting is necessary, because of the following physical and chemical characteristics of polymers:
I. Polymers have a tendency to phase-separate when molten.
II. Different polymers have very different decomposition temperatures.
III. Polymers featuring very high melting temperatures decompose into smaller molecules at high temperatures rather than melt.
IV. Molten polymers mix easily.

A) I, II, IV
B) II, III
C) I, II, III
D) all of the above

Question 23

Keratins are a family of tough and insoluble proteins that are able to form fibers. They form the hard but unmineralized (not bony) structures in amphibians, mammals and reptiles/birds. Keratin, a byproduct from the poultry industry, has recently sparked interest. Keratins are made from a high proportion of the amino acid glycine (R=H), followed by the amino acid alanine (R=-CH₃). Two neighboring strands of keratin are shown below.
To what class of polymers is Keratin quite similar?

A) polyesters, such as PET
B) polyamides, such as nylon
C) polyalkenes, such as polyacrylate
D) polyurethanes

Question 24

The polymer (PEN) synthesized from the following monomers
is

Question 25

A carbonate, which forms the backbone of polycarbonates, has the following structure,

Question 26

What small molecules can be released during Chain-Growth-Polymerization?

A) H₂O
B) NH₃
C) methanol
D) none

Question 27

Determine the repeat unit for the following polymer.

A) I
B) II
C) III
D) IV

Question 28

What is characteristic of the process of Chain-Growth Polymerization
I. In the beginning of the polymerization process, there are many oligomers (an oligomer is made from a few monomers, its chain length is short).
II. High macromolecular weights are only reached at the very end of the polymerization process.
III. The macromolecular weight of the polymer chains grows approximately linear during the time required for the polymerization process.
IV. Polymer chains grow by addition of monomers to the polymer.

A) I, II
B) II, III
C) III, IV
D) II, IV

Question 29

The structure of the polymer (Nylon 6,12), synthesized from the following monomers,
is

Question 30

Which polymers are chain-growth polymers?
I. Polyamides (e.g. Kevlar)
II. Polyesters (e.g.Mylar)
III. PVC
IV. PMMA(e.g. Lucite)

A) I, II
B) II, III
C) I, IV
D) III, IV

Question 31

A diepoxide, which forms the backbone of epoxy resins, has the following structure,

Question 32

Which polymers are chain-growth polymers?
I. nylon
II. HDPE
III. Teflon
IV. PET

A) I, II
B) II, III
C) I, IV
D) III, IV

Question 33

Principally, the anhydrous depolymerization of Chain-Growth polymers into their monomers would/will have the following advantages, compared to hydrous pyrolysis of plastics?
I. The yield of alkene-monomers, that can be repolymerized, would be higher.
II. If several monomers are formed, they can be separated by distillation.
III. The use of polymerization/depolymerization catalysts permits lower process temperatures than during the hydrous pyrolysis, in which the heat is supplied by superheated water.
IV. A greater variety of small organic compounds will be formed.

A) I, II
B) I, II, III
C) II, III, IV
D) I, III, IV

Question 34

Kapton is a polyimide developed by DuPont which has an excellent stability in the temperature range of 0K to 673K). Therefore, it is widely used in the aircraft and space industry although its resistance to mechanical wear is inferior to that of other polymers, such as Mylar (polyethylene terephthalate). Which of the following molecules can be either starting materials or intermediates in the synthesis of Kapton?

A) I, II
B) II, III
C) I, III
D) III, IV

Question 35

Which is not a step in the mechanism of a chain growth polymerization?

A) initiation
B) propagation
C) proliferation
D) termination

Question 36

Which statements are true describing the Ziegler-Natta process?
I. the process yields low density polyethylene
II. the process involves radicals
III. the original process used an alkytitanium catalyst
IV. the process yields polyethylene 3 to 10 times stronger than other methods

A) I, II
B) II, IV
C) II, III
D) III, IV

Question 37

Determine the repeat unit for the following polymer.

A) I
B) II
C) III
D) IV

Question 38

The monomers used to synthesize Nomex are

Question 39

How can one distinguish between polyethylene-terephthalate and polystyrene during the process of recycling?
I. the IR-spectra are different
II. different glass temperatures
III. different crystallinity
IV. different polymer density

A) I, II
B) II, III
C) III, IV
D) I, IV

Question 40

Which compound would react to form the polymer shown?

A) I
B) II
C) III
D) IV

Question 41

The opacity of a crystalline polymer correlates to the Tm.

Question 42

The repeat unit of polyacrylonitrile is

Question 43

The label of the following step of radical chain polymerization is __________________________.

Question 44

An elastomer with a glass transition temperature (Tg) of 25° C will lose its elasticity below 25° C.

Question 45

The monomers used to synthesize the following polyurethane are,

Question 46

Branching of polyethylene, due to a chain transfer reaction, produces low-density polyethylene (LDPE).

Question 47

Poly-3- hydroxybutanoic acid is a biodegradable polymer. Complete the reaction scheme shown below, which leads to the synthesis of poly-3-hydroxybutanoic acid.

Question 48

Complete the mechanism of the ring-opening and subsequent polymerization of caprolactam. This reaction proceeds at higher temperatures (> 150^oC).

Question 49

A polymer synthesized from the following monomers could have the form

Question 50

A polymer with a melt transition temperature (Tm) of 200° C is stronger than a polymer with a Tm of 150° C.

Question 51

A polymer synthesized from the following monomers could have the form

Question 52

The glass transition temperature (Tg) must be low for an elastomer to maintain its properties.

Question 53

The Zeigler-Natta process yields low-density polyethylene (LDPE).

Question 54

Radical chain growth polymers tend to form head to head bonds between carbon one of one monomer and carbon one of another monomer.

Question 55

The polymer synthesized from the following monomer is

Question 56

The repeat unit of polymethylacrylate is,

Question 57

Complete the mechanism for radical chain propagation begun below.

Question 58

Poly-amino-levulinic acid is a biodegradable polymer. Complete the reaction scheme shown below, which leads to the synthesis of poly-amino-levulinic acid: