Copolymerization of ethylene and 1,5-hexadiene under high pressure catalyzed by a metallocene

The copolymerization of ethylene and 1,5-hexadiene was investigated under high pressure of 1500 bar using a zirconocene catalyst in the presence of methylaluminoxane. The concentration of the diene was varied over a wide range including the homopolymerization of both ethylene and 1,5-hexadiene. From the amount of polymer formed per unit of time and the catalyst feed the productivity was determined. The resulting polymers were analyzed by DSC, GPC, IR- and C-13-NMR-spectroscopy to evaluate the average molecular weights together with the polydispersity, the crystallinity, the melting point and the structure. The catalyst exhibits a good ability for copolymerization and cyclopolymerization of 1,5-hexadiene in which a predominance of trans ring formation was observed.