Study of the molecular structure of ethylene‐propylene copolymers obtained with catalysts of different composition

Abstract

Abstract The monomer composition and sequence distribution in ethylene‐propylene copolymers (EPCs) obtained with supported titanium/magnesium (TMC) and vanadium/magnesium (VMC) catalysts as well as with titanium trichloride was studied by means of 13 C NMR spectroscopy. Based on these data ethylene‐propylene reactivity ratios were determined. The EPCs obtained on these catalysts are inhomogeneous in composition; the soluble fractions contain larger amounts of propylene. The microstructures of copolymers obtained on TMCs and TiCl 3 are similar. For EPCs obtained on VMCs, propylene “head‐to‐head” or “tail‐to‐tail” inversions and a more homogeneous distribution of propylene are observed.