Structure and physical properties of syndiotactic polypropylene from living polymerization with Bis(phenoxyimine)-based titanium catalysts

The structure and mechanical properties of syndiotactic polypropylene prepared with non-metallocene catalysts, based on titanium chlorides bearing phenoxyimine ligands are discussed. This catalyst promotes living polymerization of propylene, producing high molecular weight syndiotactic polypropylene. The effect of the presence of m dyads defects of stereoregularity, consistent with the chain-end mechanism, and defects of regioregularity, due to (1,2) misinsertions, on the crystallization behavior and mechanical properties are analyzed. The presence of m dyads defects of stereoregularity prevents the crystallization of the fully ordered antichiral helical form I.