Chemistry Reference
In-Depth Information
difference in behavior of isobutene and acrylonitrile in terms of monomer
structure.
11-2
Suggest practical ionic initiators and solvents for the ionic polymerization
of the following monomers:
(a) CH
2
Q
C(CN)
2
(b) isoprene
(c) tetrahydrofuran
(d) propylene
(e) coumarone (11-17)
11-3 Outline reaction schemes
to produce each of
the following block
copolymers:
(a) (styrene)-
x
(methyl methacrylate)-
y
(styrene)-
z
(b) (
-methylstyrene)-
x
(isoprene)-
y
(styrene)-
z
(c) (styrene)-
x
(methacrylonitrile)-
y
α
11-4
Show how you would synthesize the following block polymer:
CH
3
HH
HH
H
(
)
O
H
NC
O
OCH
2
CH
2
O
CH
2
CCCH
2
(
CH
2
C
C
CH
2
)
OCH
2
CH
2
OC
N
n
n
O
O
HN
C
O
(
O
(
CH
2
)
)
O
CN
H
4m
O
CH
3
11-5
Show the initiating step in the use of each of the following initiators. Use
an appropriate monomer in each case:
(a)
n
-C
4
H
9
Li
(b) AlCl
3
1
HCl
H
2
O
(d) Na
1
naphthalene
(e) TiCl
3
1
(c) BF
3
1
(C
2
H
5
)
3
Al
11-6 A scrupulously clean and dry solution of styrene (5 g) in 50 mL tetrahy-
drofuran was held at
70
C. Sodium (1.0 g) and naphthalene (6.0 g)
were stirred together in 50 mL dry tetrahydrofuran to form a dark green
solution of sodium naphthalide (
Eq. 11-10
). When 1.0 mL of this green
solution was injected into the styrene solution the latter turned reddish
orange. After a few minutes the reaction was complete. The color was
quenched by adding a few milliliters methanol, the reaction mixture was
allowed to warm to room temperature, and the p
oly
mer formed was pre-
cipitated and washed with methanol. What is
M
n
of the polystyrene
formed in the absence of side reactions? What should
M
w
of the product
be if the polymerization were carried out so that the growth of all
macromolecules was started and ended simultaneously?
2
