BRANCHING DISTRIBUTION AND SEQUENCE DISTRIBUTION OF ETHYLENE-1-BUTENE COPOLYMERS PREPARED WITH ZIEGLER CATALYST.

A number of studies on the sequence distributions in olefin copolymers prepared with the heterogenous Ziegler catalysts have been carried out by means of kinetic and **1**3CNMR studies. Some of these works indicate that the copolymers have a broad branching distribution, and the sequence distribution is rather complex in connection with multiple active sites. In the present study the ethylene-1-butene copolymer prepared with the heterogeneous titanium-based catalyst was separated into five fractions by successive solvent extractions, and the sequence distribution of each fraction was determined by **1**3CNMR measurements. It is concluded that the fractionation is necessary for determining the sequence distribution of copolymers mentioned above and that such copolymers have slightly alternating sequence distribution rather than Bernoullian distribution.