| Popis: |
CpVCl3 in combination with either MAO or (C6H5)3CB(C6F5)4/TEA was found a remarkably active catalyst system in butadiene polymerization relative to catalyst systems formed from a titanium analogue, Cp2VCl2 and Cp2VCl. For the CpVCl3/(C6H5)3CB(C6F5)4/TEA system, the dependencies of conversion on time, B/V mole ratio, an amount of TEA, and the dependency of molecular weight of polybutadiene on time have been examined. The catalyst system gives polymers with very high molecular weights and narrow polydispersities. The molecular weight and the conversion decrease with an increase in a feed of hydrogen gas as a chain transfer agent. The polymers consist of high 1,4-cis units and nearly 10% of 1,2-vinyl units. The sequence distribution of 1,4 and 1,2 units was found random by 13C-NMR analysis. |
