1. Draw a 4-5 repeat unit segment for each of the following polymers.
a) syndiotactic poly(vinyl alcohol)
b) isotactic poly(α-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.
3. Give the cyclic monomer, initiator and reaction conditions for the preparation of each of the following polymers:
