PROPENE-CO-BUTENE RANDOM COPOLYMERS SYNTHESIZED WITH SUPERACTIVE ZIEGLER-NATTA CATALYST

Temperature rising elution fractionation (TREF) was carried out on pro pene-co-butene random copolymers synthesized with heterogeneous Ti-bas ed Ziegler-Natta catalysts. C-13-NMR and DSC measurements were carried out on the fractions. It was found that fractionation occurred on the basis of copolymer crystallizability, which is controlled by both ste reoregularity and composition. This work also pointed out that such co polymers are blends of nearly Bernoullian macromolecules having differ ent composition. Finally, a relationship between stereospecificity and comonomer reactivity appeared from the experimental data.