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Homework for Exam #1 of Introduction to Polymer Chemistry (Dr. Bae)

1 Give the structure of the repeating unit for

poly(1,1-difluoroethylene)

poly(1-phenyl-1-methyletyelen)

poly(trans-1,4-butadiene)

poly(5-hydroxyhexanoic acid)

poly(ethylene terephthalate)

bisphenol-A polycarbonate

Nylon-6,6

2 Provide structures of monomer or polymer product of the following reactions.

O

RR

Grubs catalyst

2. Hydrogenation3. NaOH

1. Grubbs catalyst

O O

Grubs catalyst

SiO Si

O

SiOSi

O

CH3CH3

CH3

CH3

CH3CH3

CH3

CH3

n-BuLi

PN

PN

P

N

Cl Cl

Cl

ClCl

Cl

250 oC CH3ONa

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3 Free radical polymerization of vinyl monomers can give head-to-head or head-to-tail

orientation. Between the two orientations, which one would be formed primarily and explain

why.

4 In the absence of chain transfer side reactions, a free radical polymerization of styrene

with an initiator concentration of 1 x 10–3

mmol/liter gave average molecular weight of 14,000

g/mol.

What is degree of polymerization?

What is average kinetic chain length of polymerization?

If initiator concentration is increased to 2 x 10–3

mmol/liter, what will be average

molecular weight of the resulting polymer?

5 Explain differences among low-density polyethylene, high-density polyethylene, and

linear low-density polyethylene in terms of synthesis and polymer structures.

6 Explain why low-density polyethylene has low crystallinity using polymerization

mechanism.

7 Explain why polypropylene and polyisobutylene cannot be obtained in high molecular

weight by free radical polymerization.

8 Draw chemical structure of butylated hydroxytoluene and its role in polymerization of

vinyl monomer.

9 Traditionally, free radical polymerization of vinyl monomers gives a broad polydispersity

index above 3. However, controlled radical polymerization of vinyl monomers gives

polydispersity index less than 1.5. What are differences between the two radical polymerization

processes?

10 What is ceiling temperature? -Methylstyrene has a ceiling temperature of 66 °C in bulk

radical polymerization.

What will happen if you attempt to polymerize -methylstyrene using benzoyl

peroxide as initiator at 80 °C?

How can you obtain high molecular weight polymer of -methylstyrene?

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11 In free radical copolymerization of two vinyl monomers, discuss what will be polymer

composition with the following combinations

ethylene (M1) and vinyl acetate (M2) with r1 = 0.97 and r2 = 1.02

styrene (M1) and maleic anhydride (M2) with r1 = 0.041 and r2 = 0.01

styrene (M1) and vinyl acetate (M2) with r1 = 55 and r2 = 0.01

12 To prepare polystyrene-block-poly(methyl methacrylate) via living anionic

polymerization, which monomer needs to be polymerized first and explain why.

13 Explain differences between Ziegler-Natta polymerization and Metallocene-catalyzed

polymerization of olefins.

14 Although poly(vinyl chloride) is prepared by free radical polymerization of vinyl chloride,

poly(vinyl alcohol) cannot be prepared by a similar method. Explain why and provide how to

prepare poly(vinyl alcohol) commercially.