The influence of basic reaction parameters -the ratio of catalyst components, the composition of the monomer mixture and the temperatureon the progress of the copolymerization, the molecular weight and the molecular weight distribution as well as on the composition of the copolymers obtained is reported. Conversion data for the variation of the mole ratio of comonomers show a maximum for an [AI]/[V] mole ratio of approximately 7, whereas the molecular weight of copolymers is not significantly influenced. An increase in the molecular weight of the copolymers can be obtained by an increase of butadiene content in the monomer mixture. However, there is also an increasing incorporation of butadiene into the copolymer. Raising the temperature from -60 "C to 0 "C results in a significant decrease in molecular weight, whereas the composition of the copolymers is not significantly changed.

ZUSAMMENFASSUNG:Es SUMMARY:The copolymerization of butadiene and ethene in the presence of the catalyst dineopentyloxyvanadiumoxychloride/triisobutylaluminum was investigated. Basic reaction parameters, such as the [AI]/[V] ratio, the composition of monomer mixture and the polymerization temperature result in a significant influence on the progress of reaction, the conversion of monomers and on the molecular weight and polydispersity of copolymers obtained. NMR measurements demonstrate a high degree of alternation.A maximum of conversion and molecular weight was found by variation of the ratio of catalyst components at [AI]/[V] = 7. An increase of ethene content in the monomer mixture also results in a maximum of conversion but, in contrast, in a continuous decrease in molecular weight. The increase of polymerization temperature from -25°C up to +40"C results in different effects on the yield of copolymers and appropriate data of molecular weight. The microstructure of products with a high content of trans-butadiene units exhibits an increase of 1,2-addition of butadiene and the beginning of crosslinking reactions at temperatures above 20 "C.

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