2015 HW 1 Intro Polymer Chem Bae
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Transcript of 2015 HW 1 Intro Polymer Chem Bae
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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.