Syndiotactic polypropylene — synthesis and properties
Polimery 1997, No 10, 595
Propylene was polymerized with MAO-activated metallocene catalyst Ph2C(CpFlu)ZrCl2 [η5, η5’ -l,9'-diphenylmethylidene-(cyclopentadienyl)(fluorenyl)]-dichlorozirconium (IV) and properties of the resulting syndiotactic PP (sPP) were measured. The catalytic system selected allowed to achieve high polymerization rates and high values of molecular weight and syndiotacticity of the polymer. Studies on the M„vs. [H2] relationship gave the ratios of the polymer chain propagation and monomer- and/or hydrogen caused chain transfer rate constants. 13C-NMR spectroscopy data showed each PP to havean almost identical pentad content. As compared with isotactic polypropylene (iPP), sPP is much more elastic and exhibits the higher impact strength.