do just the q 4,5,6
mon25
polymer_hw_copy.doc1. Draw a 4-5 repeat unit segment for each of the following polymers.
a) syndiotactic poly(vinyl alcohol)
b) isotactic poly(-methylstyrene)
c) cis-1,4-polychloroprene
d) trans-1,4-poly(2,3-dimethyl-1,3-butadiene)
2. Based upon the Zieglar-Natta mechanism discussed in class, suggest explanations for each of the following observations.
a) Metal-polymer bonds are often found in polymers made by Z-N catalysis.
b) Addition of hydrogen to a Z-N polymerization lowers the molecular weight of the polymer produced.
c) Increasing the concentration of aluminum alkyl (AlR3) in a Z-N reaction increases the polymerization rate to a maximum. If more AlR3 is added, the rate remains constant or decreases.
d) Z-N polymerization at low temperature tends to yield syndiotactic polymers.
N
H
C
H
C
O
C
H
2
C
H
3
n
3. Give the cyclic monomer, initiator and reaction conditions for the preparation of each of the following polymers:
C
H
C
H
(
C
H
2
)
2
n
n
O
(
C
H
2
)
2
O
C
H
2
a) b) c)
C
H
3
a) b) c)
5. Using rA and rB values from Table 9.1 in the text, construct plots showing copolymer composition as a function of feed composition for the following monomer pairs.
a) styrene and acrylonitrile b) vinyl chloride and vinyl acetate
6. Determine the azeotropic composition of a copolymer formed from styrene and acrylonitrile.
7. Outline reaction schemes to prepare the following block copolymers.
a) –(styrene)x-(methyl acrylate)y-(styrene)x- b) –(styrene)x-(methacrylonitrile)y-
C
O
(
C
H
2
)
4
O
C
O
N
H
O
H
N
C
H
3
C
H
3
N
H
N
H
C
O
O
C
O
O
C
H
C
H
2
C
H
2
C
H
C
H
2
C
H
C
H
C
H
2
n
n
m
c)
