Polar Isotactic and Syndiotactic Polypropylenes by Organozirconium-Catalyzed Masking-Reagent-Free Propylene and Amino-Olefin Copolymerization.

Abstract

Polar functionalized isotactic and syndiotactic polypropylenes (PPs) are synthesized by direct, masking-reagent-free propylene and amino-olefin (AO, CH2 =CH(CH2 )x Nn Pr2 , x=2, 3, 6) copolymerizations using the activated precatalysts rac-[Me2 Si(indenyl)2 ]ZrMe2 and [Me2 C(Cp)(fluorenyl)]ZrMe2 , respectively. Polymerization activities at 25 °C are as high as 4208 and 535 kg/(mol h atm) with AO incorporation up to 4.0 mol % and 1.6 mol %, respectively. Remarkably, introducing the amino-olefin comonomers significantly enhances stereoselection for both isotactic (mmmm: 59.5 %→91.0 %) and syndiotactic (rrrr: 66.3 %→81.3 %) products.