process and composition for the preparation of a catalytic alpha - olefin polymers or copolymers having a high index of isotatticita.

摘要

A process for making crystalline polymers or copolymers of alpha-olefins containing 3 to 8 carbon atoms, such as polypropylene, by polymerization with a catalyst consisting of a combination of titanium chloride and an organic aluminum compound, in the presence of a stereospecificity additive. This stereospecificity additive has the formula: R1-O-(CpH2p)-S-R2, where: R1 and R2 are alkyl radicals containing 1 to 4 carbon atoms or are linked together to form a divalent -(CmH2m)-radical, and p and m are integers each with a value of 1 to 6; this additive may be used in the presence of an activator.