MICROTACTICITY OF ETHYLENE-PROPYLENE COPO LYMERS PREPARED WITH SUPPORTED CATALYSTS OF DIFFERENT COMPOSITION

Microtacticity of propylene triads in ethylene-propylene copolymers pr epared with supported titanium-magnesium catalysts of different stereo specificity, vanadium-magnesium catalysts of VCl4/MgCl2 + AlR(3) type, and Zr(BH4)(4)/SiO2 and CrO3/SiO2 catalysts (both are active without organoaluminum cocatalysts) was studied by C-13 NMR spectroscopy. Copo lymers prepared with titanium-magnesium catalyst containing stereoregu lating additives show the highest microtacticity. Copolymers synthesiz ed with catalysts of lower regiospecificity, especially with the chrom ium oxide catalyst, show minimal microtacticity of the propylene triad s.