Investigation of diene addition on ethylene–propylene (EP) copolymerization with a zirconocene catalyst: Effects of diene types and E/P ratios

In the present study, the polymerization behaviors of ethylene–propylene (EP) copolymerization with a zirconocene/MAO catalyst upon the addition of a small amount of diene were investigated. It indicated that besides the addition of dienes, the polymerization behaviors were also dependent on the E/P ratios and types of diene. Apparently, diene addition resulted in decreased activity, especially at high E/P ratio (E/P = 3). In all cases, the addition of 1,4 hexadiene (1,4 HD) resulted in the lowest activities. It seemed that there was no significant change in the microstructure of EP elastomers upon different E/P ratios. The characteristics of polymer obtained by means of DSC and 13C NMR were further discussed in more detail.