COPOLYMERIZATION OF ETHYLENE AND VINYLCYCLOHEXANE USING SOLUBLE ZIEGLER-NATTA CATALYSTS

The copolymerization of ethylene and vinylcyclchexane has been investi gated using soluble catalytic systems Cp2ZrCl2/MAO (Cp = eta4 cyclopen tadienyl; MAO=methylaluminoxane) and Cp2ZrMe2/MAO at 70-degrees-C and room temperature. Under the reaction conditions employed, up to 1.7 mo l% ef vinylcyclohexane could be introduced into the polyethylene chain s. The molecular structure and comonomer content of the copolymers wer e determined by C-13 nuclear magnetic resonance. The comonomer content of the polymers was found to increase with the comonomer concentratio n in the feed. The comonomer was found to be mainly statistically dist ributed. With samples containing higher comonomer content, however, th e formation of a relatively very small amount of short blocks was note d. The average molecular weights of the copolymers were lower than tho se of pure polyethylene prepared under identical conditions. As expect ed, the vinylcyclohexane decreased the melting point and crystallinity of the polymers.