Copolymerization of Propylene and Polar Allyl Monomer with Zirconocene/Methylaluminoxane Catalyst:  Catalytic Synthesis of Amino-Terminated Isotactic Polypropylene

The copolymerizations of propylene with allyl monomers carrying alcohol or amine were conducted by the rac-dimethylsilylbis(1-indenyl)zirconium dichloride/methylaluminoxane catalyst system. The allyl monomers were pretreated by alkylaluminum before the polymerization. Although the efficiency of the introduction of allyl alcohol-based comonomer was extraordinary low (0.04−0.08 mol % in polymer), the trimethylaluminum-treated allylamine was found to be introduced more effectively (0.65 mol % in polymer). The 13C NMR study indicated that the position of allylamine unit in the copolymer was influenced by the kind of alkylaluminum used at the polymerization. In the presence of trimethylaluminum, the terminally aminated polypropylene was obtained ([amino end polymer]/[whole polymer] = 0.83). In the presence of triisobutylaluminum, however, the allylamine unit is located both on the main chain and at the chain end. The end-aminated polymer was probably obtained due to the formation of dormant species after the i...