Chemistry Reference
In-Depth Information
10
─
4
5. In the above polymerization, the transferring constant to monomer,
C
M
¼
3.74, the
10
─
4
transferring constant to solvent,
C
S
¼
5.6
and transferring constant to the initiator,
10
─
5
,
C
I
¼
0.75. Assuming that
f ¼
0.72, and
k
t
is 7.2
k
p
is 176/mol, (
k
d
is shown above)
calculate
R
p
and the average DP.
Section 3.6
1. Explain what is meant by reactivity ratios and how they are derived.
2. Write the copolymerization equation. In a copolymerization of 1 mol of styrene with 1 mol of
butadiene,
r
1
¼
0.78 and
r
2
¼
1.39, what is the expected composition of the copolymer at the
early stages of the polymerization?
3. How do substituents on the monomer molecules affect reactivity of the monomers toward
attacking radicals?
4. Explain the
Q
and
e
scheme and write the Price-Alfrey equation.
5. How can
values. Show the relationship.
6. From chemical structures alone predict the products from free-radical copolymerizations of pairs
of (1) styrene and methyl methacrylate, (2) styrene and vinyl acetate, (3) methyl methacrylate and
vinyl chloride. Consult Table
3.8
for reactivity ratios.
r
1
and
r
2
be derived from the
Q
and
e
Section 3.7
1. How many reactivity ratios are there in a terpolymerization?
2. Write the equation for the terpolymerization reaction.
Section 3.8
1. What is allylic polymerization? If allyl alcohol does not polymerize to a high-molecular-weight
polymer by free-radical polymerization, why does triallyl cyanurate form a high-molecular-weight
network structure by the same mechanism?
Section 3.9
1. What is inhibition and retardation? Explain.
2. Give an example of a good inhibitor and a good retarder and show by chemical equations the
reaction with free radicals.
3. Show the reaction of quinone with free radicals.
4. Write the equation that relates rate data to inhibited polymerizations.
5. Calculate
R
p
for the polymerization of 1 mol of styrene containing 0.01 mol of hydroquinone
inhibitor. with
10
─
5
.
k
p
¼
176/mol and
k
t
¼
7.2
