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mon25
123copy_2.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)
