CHARACTERISTICS OF ETHYLENE-PROPYLENE AND PROPYLENE-1-BUTENE COPOLYMERIZATION OVER TICL3.1/3ALCL3-AL(C2H5)2CL

An ethylene-propylene (13EP) copolymer containing 0.41 mol % 13C-enriched ethylene has been fractionated on an isotactic basis by a temperature-programmed elution column technique. The 13C NMR analysis of the fractions indicates that the ethylene content decreases as the isotacticity increases. The atatic fraction eluted at 20°C is about 6 times as high in ethylene content as the isotactic fractions eluted over 110°C. This fact well accounts for a wide copolymer composition distribution generally found in ethylene-propylene copolymerization prepared with heterogeneous catalysts. A 1-butene-propylene (13BP) copolymer containing 0.20 mol % 13C-enriched 1-butene has been examined similarly. In this case, the 1-butene content of the fractions is almost uniform.