The DSC melting curves of lthylene/propylene copolymers double melting peaks

and he crystallite melting process was a wide temperature range. The ether and hexane fractionation gave randomly distributed low crystallinie ethylene/propylene copolymers

whereas the heptane fractionation gave copolymer containing long ethylene sequences with high ethylene content and high crystallinity. The latter has showed longest ethylene sequence length () (5.156) and largest r1

r2 value for 13C-NMR results. These results can be attributed to the inter-molecular non-homogeneity and can be explained by the existence ofmulti active-centers in the catalytic system.